| Yuji Oki | Last modified date：2024.04.25 |
Professor /
Integrated Electronics /
Department of Electronics /
Faculty of Information Science and Electrical Engineering
Papers
| 1. | Yamagishi, H., Fujita, K., Miyagawa, J., Mikami, Y., Yoshioka, H., Oki, Y., Takada, N., Baba, S., Saito, S., Someya, S., Lin, Z. H., Huang, J. S. & Yamamoto, Y., Pneumatically Tunable Droplet Microlaser, Laser and Photonics Reviews, 10.1002/lpor.202200874, 17, 5, 2200874, 2023.05, An ideally flexible laser may function in unison with minute fluctuations in nature. Lasers made solely from liquids are promising toward this end, but they are intrinsically unstable and have been inapplicable to steady operation under ambient conditions unless they are enclosed in a tailored container or a matrix to prevent the evaporation of the liquid. Here, a simple methodology is reported to form a self-standing spherical microlaser that is composed fully of liquid and operates steadily even under atmosphere. The robustness and spherical morphology of the droplets are achieved by using ionic liquid as the liquid medium and gently casting the droplets on a substrate covered with hydrophobic nanoparticles to enhance the metastability of the contact angle. The resulting droplets are highly robust and work as efficient long-lasting laser oscillators. The lasing wavelength is sensitively shifted when the droplets are subjected to a faint breeze or moisture, which is associated with the deformation of the droplet. The morphological and optical responses of the droplet under gas convection are consistently supported by aerodynamic and electromagnetic simulations. The droplets are readily scalable with an inkjet printer without the need for any further treatments.. |
| 2. | Takeda, H., Abazi, A., Eich, A., Tomishige, Y., Hiramoto, K., Chen, J., Mikami, Y., Tate, N., Oki, Y., Schuck, C., Yoshioka, H., Ultrasmall Submicrometer Sized Periodic Deposition on the Si3N4 Microring with Nanodispensing Technique, 2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023., 10.1109/CLEO/EUROPE-EQEC57999.2023.10232309, 2023.06. |
| 3. | Chen, J., Nasir, A., Abazi, A., Eich, A., Tomishige, Y., Takeda, H., Mikami, Y., Tate, N., Oki, Y., Schuck, C. Yoshioka, H., Active Clad Microring Laser with Diffraction Grating for Mutual Coupling of Radial Direction Mode and WGM, 2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023., 10.1109/CLEO/EUROPE-EQEC57999.2023.10232578, 2023.06, Active microring resonators with whispering gallery mode (WGM) are efficient on-chip light sources. Previously, demonstrations such as semiconductor microrings integrated with gratings for single-mode lasing have been reported [1]. These devices are active-core lasers with gain material contained in the resonant cavity and the laser mode dominated by the WGM. On the other hand, there are also active-cladding lasers, in which a light-emitting polymer is spin-coated onto a linear grating to form an active layer and achieve a continuously tunable wavelength [2]. Although an active-cladding-type laser with a grating integrated microring structure has not yet been reported, if it is demonstrated, propagation modes in radial direction inside the ring can be expected in addition to the microring-specific WGM. In other words, a unique laser device in which different propagating mode groups coexist and are mutually coupled via a diffraction grating on rings can be realized. In this study, we fabricated an active-cladding-type microring laser by spin-coating a laser dye-added polymer onto a Si3N4 microring with a diffraction grating and demonstrated and analyzed the coexistence of WGM and radial direction mode for the first time.. |
| 4. | Du, H., Takeda, H., Kadowaki, T., Tate, N., Kawazoe, T., Oki, Y., Ohtsu, M., Hayashi, K., Revelation and analysis of optical phase delay exhibited by Al-doped 4H-SiC due to current induction, 2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, 10.1109/CLEO/EUROPE-EQEC57999.2023.10232613, 2023.06, Magneto-optical (MO) effect-based devices, such as spatial light modulators and optical isolators, have become increasingly prevalent in the fields of optical communication and information processing because of their high-speed response. However, conventional MO devices (e.g., Terbium Gallium Garnet crystals) have poor transparency in the visible range and polarization rotation capability, which constrains the integration of small optical systems. Recently, a silicon carbide spatial light modulator (SiC-SLM) (depicted in Fig. 1(a)) was developed via dressed-photon-phonon (DPP)-assisted annealing of 4H-SiC crystals doped with aluminum atoms [1]. This device exhibited an extremely large MO effect in the visible range, as evidenced by a Verdet constant of 9.51×104 rad/T•m near its absorption edge at 457 nm. There are many unknown aspects such as the spatial distribution of the degree of polarization rotation, optimal annealing conditions, and geometrical conditions of the electrode. In this study, the utilization of the SiC-SLM for spectral filtering of imaging technology and the photophysical properties of the SiC-SLM device, especially the phase delay by birefringence, were investigated, and this progress promises a new SLM application.. |
| 5. | Junfeng Zhu, Shuxuan Liu, Yiqin Xu, Jingchao Xing, Boqian Chen, Zhiliang Gu, Zhiqing Zhang, Chenxi Zhao, Atsushi Harada, Hiroaki Yoshioka, Yuji Oki, Phase wavefront perturbation calculation model for spectroscopic refractive index matching of hybrid materials, APPLIED OPTICS, 10.1364/AO.486863, 62, 13, 3330-3337, 2023.05, A low-cost flexible spectroscopic refractive index matching (SRIM) material with bandpass filtering properties without incidence angle and polarization dependence by randomly dispersing inorganic CaF2 particles in organic polydimethylsiloxane (PDMS) materials was proposed in our previous study. Since the micron size of the dispersed particles is much larger than the visible wavelength, the calculation based on the commonly used finite-difference time-domain (FDTD) method to simulate light propagation through the SRIM material is too bulky; however, on the other hand, the light tracing method based on Monte Carlo theory in our previous study cannot adequately explain the process. Therefore, a novel approximate calculation model, to the best of our knowledge, based on phase wavefront perturbation is proposed that can well explain the propagation of light through this SRIM sample material and can also be used to approximate the soft scattering of light through composite materials with small refractive index differences, such as translucent ceramics. The model simplifies the complex superposition of wave -front phase disturbances and the calculation of scattered light propagation in space. The scattered and nonscattered light ratios; the light intensity distribution after transmission through the spectroscopic material; and the influence of absorption attenuation of the PDMS organic material on the spectroscopic performance are also considered. The simulation results based on the model are in great agreement with the experimental results. This work is important to further improve the performance of SRIM materials.(c) 2023 Optica Publishing Group. |
| 6. | Yushi Yoshioka, Daichi Takagoshi, Keisuke Nakakubo, Takuji Kotani, Hiroaki Yoshioka, Oki Yuji, Development of Tunable DFB-Flexible Laser Based on Silicone Elastomer, The 75th Joint Conference of Electrical, Electronics and Information Engineers in Kyushu, 222-223, 2022.09, [URL]. |
| 7. | Yoshitaka Tomishige, Kota Hiramoto, Yuya Mikami, Abdul Nasir, Yuji Oki, Hiroaki Yoshioka, Fabrication of High Refractive Index Microdisk for Integration into Si3N4 Optical Integrated Circuits by Printing Method, The 75th Joint Conference of Electrical, Electronics and Information Engineers in Kyushu, 220-221, 2022.09, [URL]. |
| 8. | Jinghan Chen, Abdul Nasir, Adrian Abazi, Alexander Eich, Yuya Mikami, Naoya Tate, Yuji Oki, Carsten Schuck, Hiroaki Yoshioka, , Grating Integrated Si3N4 Microring Laser Based on Active Cladding by Dye-Doped Polymer: Discussion on Stopband and Free Spectral Range, , 2022.09., The 75th Joint Conference of Electrical, Electronics and Information Engineers in Kyushu, 218-219, 2022.09, [URL]. |
| 9. | Daichi Takagoshi, Keisuke Nakakubo, Yuya Mikami, Yushi Yoshioka, Nasim Obata, Takuji Kotani, Hiroaki Yoshioka, and Yuji Oki, Regenerative DFB Lasing From new Silicone Elastomer Waveguide for Printable and Imprintable Optics Fabrication, Technical Digest CLEO: 2022, https://doi.org/10.1364/CLEOPR.2022.CThP1G_05, 2022.05, [URL]. |
| 10. | Hiroshi Yamagishi, Keitaro Fujita, Junnosuke Miyagawa, Yuya Mikami, Hiroaki Yoshioka, Yuji Oki, Naoki Takada, Soumei Baba, Shimpei Saito, Satoshi Someya, Zhan-Hong Lin, Jer-Shing Huang, Yohei Yamamoto, Pneumatically Tunable Droplet Microlaser, Laser & Photonics Reviews, 10.1002/lpor.202200874, 17, 2, 2023.02, Abstract : An ideally flexible laser may function in unison with minute fluctuations in nature. Lasers made solely from liquids are promising toward this end, but they are intrinsically unstable and have been inapplicable to operation under ambient conditions. Here, we report a self-standing droplet microlaser that operates steadily even under atmosphere. An ionic liquid spontaneously forms a spherical microdroplet featuring a metastable contact angle and works as an efficient long-lasting laser oscillator. The droplet is far more deformable than plastics, and its lasing wavelength is sensitively altered when it is subjected to a faint breeze or moisture. The morphological and optical responses are consistent with aerodynamic and electromagnetic simulations. The droplets are readily scalable with an inkjet printer without the need for any further treatments. Keywords : Laser Oscillation, Ionic Liquid, Microfluidics, Droplet, Computational Fluid Dynamics, Phase-field Method, Finite-Difference Time-Domain Simulation Cite this article : Yamagishi, H.; Fujita, K.; Miyagawa, J.; Mikami, Y.; Yoshioka, H.; Oki, Y.; Takada, N.; Baba, S.; Saito, S.; Someya, S.; Lin, Z.-H.; Huang, J.-S.; Yamamoto, Y. Pneumatically Tunable Droplet Microlaser. Laser Photon. Rev. 2023, Vol. 17, in press. https://doi.org/10.1002/lpor.202200874. |
| 11. | Kota Hiramoto, Nasim Obata, Alexander Eich, Yuya Mikami, Abdul Nasir, Naoya Tate, Yuji Oki, Carsten Schuck, Hiroaki Yoshioka, Direct printing of organic micro-disk cavity lasers on waveguides in optical integrated circuits, Conference on Lasers and Electro-Optics/Pacific Rim 2022, CTuP11E_03, 2022.08. |
| 12. | Nasim Obata, Yuya Mikami, Hiroaki Yoshioka, Yuji Oki, Embedding Optical Microcavities in Nanoporous SiO2 Film via Infill Inkjet Printing, Advanced Photonics Research, 10.1002/adpr.202200018, 3, 8, 2200018-2200018, 2022.08. |
| 13. | Keisuke Nakakubo, Daichi Takagoshi, Yuya Mikami, Hiroaki Yoshioka, Takuji Kotani, Yuji Oki, Solid phase dye molecular dispersion property of PDMS-based thermoplastic elastomer, Optical Materials Express, 10.1364/ome.446342, 12, 1, 196-196, 2022.01. |
| 14. | 偏光依存性を導入したナノポーラスマイクロキャビティの新しい屈折率モデルの開発. |
| 15. | Direct printing of Microdisk into High Transparency Nanoporous SiO2 Film. |
| 16. | Junfeng ZHU, Lei WAN, Chenxi ZHAO, Ryo SAKAI, Yuya MIKAMI, Tianhua FENG, Cong CHEN, Weiping LIU, Hiroaki YOSHIOKA, Zhaohui LI, Yuji Oki, Tunable and flexible deep-ultraviolet bandpass filters based on micro- and nanoparticle/polydimethylsiloxane hybrid membranes, OPTICAL MATERIALS, 10.1016/j.optmat.2021.111073, 115, 2021.05. |
| 17. | Abdul Nasir, Yuya Mikami, Rui Yatabe, Hiroaki Yoshioka, Nilesh Vasa, Yuji Oki, Fully room temperature and label free biosensing based on an ink-jet printed polymer microdisk laser, Optical Materials Express, 10.1364/ome.415000, 11, 3, 592-592, 2021.03. |
| 18. | Junfeng Zhu, Chenxi Zhao, Ryo Sakai, Hiroaki Yoshioka, Yuji Oki, The particle size distribution influence on the spectroscopic performance of CaF2 dispersed PDMS hybrid materials, Proc. of SPIE 2021, 10.1117/12.2581237, 11682, 116821I, 2021.01, A novel UV transparent visible scattering spectroscopic material based on refractive index matching by dispersing specific CaF2 particles into the PDMS matrix was proposed. This hybrid material can be used to develop a UV bandpass filter that showed high transmittance around 260-280 nm and wider bandwidth in the UV region. Furthermore, micro-CaF2 particle size with narrower size distribution that can be fabricated by grinding, precipitation, and centrifugal separation, showed narrower bandwidth of transmittance spectra after dispersing in the PDMS matrix.. |
| 19. | Keisuke Nakakubo, Hiroki Inoue, Hiroaki Yoshioka, Kinichi Morita, Takuji Kotani, Yuji Oki, Flexible waveguides composed of PDMS based elastomer by pen-drawing technique for printable optics, Proc. SPIE 2021, 10.1117/12.2582700, 11682, 116820J, 2021.01. |
| 20. | Junfeng Zhu, Chenxi Zhao, Ryo Sakai, Hiroaki Yoshioka, Yuji Oki, The particle size distribution influence on the spectroscopic performance of CaF2dispersed PDMS hybrid materials, Proc. of SPIE, 116821I, 2021.01, A novel UV transparent visible scattering spectroscopic material based on refractive index matching by dispersing specific CaF2 particles into the PDMS matrix was proposed. This hybrid material can be used to develop a UV bandpass filter that showed high transmittance around 260-280 nm and wider bandwidth in the UV region. Furthermore, micro-CaF2 particle size with narrower size distribution that can be fabricated by grinding, precipitation, and centrifugal separation, showed narrower bandwidth of transmittance spectra after dispersing in the PDMS matrix.. |
| 21. | Junfeng Zhu, Chenxi Zhao, Ryo Sakai, Yuya Mikami, Hiroaki Yoshioka, Yuji Oki, Development of light scattering model of micro-nano hybrid spectroscopic compound for SOT module UV application, レーザー学会学術講演会第41回年次大会, 2021.01. |
| 22. | Harunobu Takeda, Hiroaki Yoshioka, Hiroaki Minamide, Yuji Oki, Chihaya Aadachi, 0.5–4.5THz band terahertz spectroscopy of thermally activated delayed fluorescence molecules, Optics Communications, 10.1016/j.optcom.2020.126339, 476, 2020.12, In this work we performed an expanded THz range spectroscopic analysis of organic electroluminescence chromophores; specifically the thermally activated delayed fluorescence (TADF) compounds 4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene (2CzPN), 2,3,5,6-tetrakis(carbazol-9-yl)-1,4-dicyanobenzene (4CzTPN) and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as amorphous powders. THz parametric oscillator, injection seeded THz parametric generator, THz time-domain and Fourier transform infrared spectroscopy techniques were all used to assess these compounds over the frequency ranges of 0.50–4.5 and 18–54THz. The resulting experimental spectra were compared with the results of density functional theory (DFT) calculations at the M06-2X/6-31G(d,p) level of theory. THz absorption bands in the experimental spectra were found to be very weak because of the lack of crystallinity in these specimens, even though the DFT calculations predicted absorbance in the THz range. Based on the DFT results, the absorbance lines that were observed are attributed to the wagging, rocking, rotational and out-of-plane bending motions of the carbazole moieties.. |
| 23. | Ishimatsu, Ryoichi; Shimizu, Shinichi; Hongsibsong, Surat; Nakano, Koji; Malasuk, Chacriya; Oki, Yuji; Morita, Kinichi, Enzyme-linked immunosorbent assay based on light absorption of enzymatically generated aniline oligomer: Flow injection analysis for 3-phenoxybenzoic acid with anti-3-phenoxybenzoic acid monoclonal antibody, TALANTA, 10.1016/j.talanta.2020.121102, 218, 2020.10. |
| 24. | Kamil STRZELAK., Chacriya MALASUK, Yuji OKI, Kinichi MORITA, Ryoichi ISHIMATSU, 3D printed silicone platforms with laser-scattering protein detection under flow analysis conditions as a development of Silicone Optical Technology (SOT), Microchemical Journal, 10.1016/j.microc.2020.104936, 157, 104936, 2020.09, In this work, the 3D printed silicone microfluidic systems with simultaneous laser-scattering detection for turbidimetric and nephelometric measurements are presented. As a model reaction, the Exton method for total protein determination has been chosen as the well-known analytical protocol. Presented research is a development of recently presented idea of Silicone Optical Technology (SOT). It can be considered as the next step for all-in-one 3D printed analytical system concept, which means that microfluidic platform as well as detection system parts can be constructed during one-step manufacturing process. During the investigations, three microfluidic platforms with different flow-mixing patterns were designed and optimized for flow rate and sample injection volume. The most promising system with so-called 3D mixing (mixing channel along three axes) was characterized by analytical parameters sufficient for total protein analysis: limit of detection of 3 mg/L, linearity in the range of 16 – 400 mg/L and 50 µL sample consumption. The analytical usefulness of developed microfluidic platform was proved by analysis of urine samples. Furthermore, the design and setting up of double detection system based on Arduino microcontroller have been discussed.. |
| 25. | Chacriya Malasuk; Ryoichi Ishimatsu; Kinichi Morita; Hiroaki Yoshioka; Yuji Oki, Flow-through optical device based on silicone optical technology (SOT) for determination of iron in drinkable tap water, MICROCHEMICAL JOURNAL, 10.1016/j.microc.2020.104897, 157, 2020.09, We propose a new concept “silicone optical technology (SOT)”, with low noise and simple integration of all optical components, and use a common matrix of polydimethylsiloxane (PDMS) as a prototype for rapid digital fabrication. This work involves the rapid design and fabrication of SOT optical modules designed to be coupled with a flow injection analysis system (SOT-FIA module), and their use in combination with a handheld photo absorbance meter “picoExplorer™” is also demonstrated. A digital fabrication method, by casting PDMS on the three-dimensional printed mold/frame, is developed. A simple structure of transparent PDMS mixed with the white pigment of titanium dioxide (TiO2) rutile particle (W-PDMS) optical core with a cladding of carbon black dispersed PDMS (K-PDMS) is fabricated. This structure performs as a tiny and straightforward optical filter and shows the ability to trap tilted incident light. The addition of the white pigment into PDMS results in a special enhancement of the optical sensitivity by increasing the amount of scattered light. This module is directly mounted on a white light emitting diode (LED) and the red-green-blue (RGB) sensor device from the picoExplorer at 45° to the flow channel to increase the detection length. The optical properties of the SOT-FIA module, which arise from the presence of white PDMS (W-PDMS) and the effect of the detection length, are investigated and show a dramatically enhanced sensitivity (30–45 times) of the optical detection compared with the calculation using Beer-Lambert's law. Moreover, lower than 1% of crosstalk is observed, which indicates the low noise level detection of the proposed SOT-FIA optical device. This proposed SOT-FIA module integrated with an LED detection system is developed to be combined with a flow injection analysis system for the colorimetric detection of iron in drinkable tap water samples. The results show excellent linearity, the ability for a wide range of chemical analysis, low detection limit, high percentage recovery, high precision and good agreement with the conventional spectrophotometric method. Furthermore, the tilted and tilt-shifted coupling alignments are newly developed and evaluated.. |
| 26. | ナノポーラス薄膜への光導波路構造の直接. |
| 27. | Development of integrated spectral filter that down converts specific ultraviolet wavelength (II). |
| 28. | Chenxi Zhao, Junfeng Zhu, Kinichi Morita, Hiroaki Yoshioka, Yuji Oki, Study on the effect of particle size for the UV spectroscopy of a novel CaF2 dispersed PDMS spectroscopic material, The 73th Joint Conference of Electrical, Electronics and Information Engineers in Kyushu, 2020.09. |
| 29. | Nasim OBATA, Yuya MIKAMI, Taku TAKAGISHI, Hiroaki YOSHIOKA, Yuji OKI, Direct-printing Method of Waveguide and Flow-channel on Transparent Nano-porous SiO2 Film, 2020 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2020 - Proceedings, 10.1364/CLEOPR.2020.C7H_6, 9255988, 2020.08, We demonstrated novel strategy broadly designing RI, focusing on nano-porous structure. Mixing different shaped nano-silica, RI was successfully tuned from 1.23 to 1.33. Microdisk cavity with fine edge was also fabricated.. |
| 30. | Yuya MIKAMI, Hiroaki YOSHIOKA, Nasim OBATA, Taku TAKAGISHI, Sangmin HAN, Yuji OKI, Broadly Refractive Index Design for Porous Microdisk by Tuning Nano-porous Structure, 2020 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2020 - Proceedings, 10.1364/CLEOPR.2020.C7H_3, 9256108, 2020.08, We demonstrated novel strategy broadly designing RI, focusing on nano-porous structure. Mixing different shaped nano-silica, RI was successfully tuned from 1.23 to 1.33. Microdisk cavity with fine edge was also fabricated.. |
| 31. | Abdul NASIR, Yuya MIKAMI, Taku TAKAGISHI, Rui YATABE, Hiroaki YOSHIOKA, Yuji OKI, Effect of Edge Angle of Ink-Jet Printed Microdisk Lasers on Mode Shift Due to Protein Adsorption, 2020 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2020 - Proceedings, 10.1364/CLEOPR.2020.C2D_2, 9255993, 2020.08, Hyper branched polymer FC-V-50 based microdisk lasers with different edge angles were fabricated by ink-jet printing method. Then, effect of edge angle on mode shift was investigated by monitoring the physical adsorption of BSA protein.. |
| 32. | Takagishi, Taku; Yoshioka, Hiroaki; Mikami, Yuya; Oki, Yuji, On-demand inkjet-printed microdisk laser with air cladding by liquid flow microetching, APPLIED OPTICS, 10.1364/AO.396061, 59, 21, 6340-6346, 2020.07. |
| 33. | Taku Takagishi, Hiroaki Yoshioka, Yuya Mikami, Yuji Oki, On-demand inkjet-printed microdisk laser with air cladding by liquid flow microetching., Applied optics, 10.1364/AO.396061, 59, 21, 6340-6346, 2020.07, We have novelly, to the best of our knowledge, developed the liquid flow microetching method that can treat a single microdisk in a microregion with precise position control for inkjet-printed microdisk lasers. The injection-drain wet etching setup consisted of two microneedles that successfully performed a formation of a fine undercut structure of an inkjet-printed microdisk on a pre-pedestal layer through the individual wet etching process. Then measurement of the undercut structure using scanning electron microscopy and lasing characteristics with whispering gallery modes were carried out to demonstrate performance of the etched microdisks. The measured lasing threshold decreased by half compared with that of the unetched microdisk directly printed on a fluorine-type film. A point to note is that this etching method exhibits an excellent undercut and lasing characteristics even when using a clad pre-pedestal layer having a refractive index higher than that of core microdisks. This technique, combined with inkjet printing, offers a powerful tool for individually designing a microdisk and can help develop novel devices that comprise several inkjet-printed microdisks being evanescently coupled.. |
| 34. | Abdul Nasir, Yuya Mikami, Taku Takagishi, Rui Yatabe, Hiroaki Yoshioka, Nilesh J. Vasa, Yuji Oki, Fully room temperature bio-sensing using active microdisk fabricated by ink-jet printing method, 2020 Conference on Lasers and Electro-Optics, CLEO 2020 2020 Conference on Lasers and Electro-Optics, CLEO 2020 - Proceedings, 10.1364/CLEO_AT.2020.AW3K.5, 2020.05. |
| 35. | Junfeng Zhu, Ryo Sakai, Chenxi Zhao, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Development of ultraviolet down conversion filters based on scattering filter materials, 2020 Conference on Lasers and Electro-Optics, CLEO 2020 2020 Conference on Lasers and Electro-Optics, CLEO 2020 - Proceedings, 10.1364/CLEO_AT.2020.JTu2F.6, 2020.05. |
| 36. | Suherman Suherman, Ghilma Milawonso, Kinichi Morita, Hitoshi Mizuguchi, Yuji Oki, Statistical Evaluation of Conventional and Portable Instrumentations for Cr(VI) Analysis on Chemistry Laboratory, Key Engineering Materials (Volume 840), 10.4028/www.scientific.net/KEM.840.406, 840, 406-411, 2020.04, [URL], The development of portable instrumentation for heavy metals analysis was increased rapidly. However, the quality of data from portable methods has so far been questioned when compared to conventional instrumentation. In this research, a comparative study of conventional and portable instrumentations for Cr(VI) analysis on liquid waste water of Chemistry Laboratory at Universitas Gadjah Mada (UGM) was conducted. This research started with validation and statistical evaluation of instrumentation methods which are UV-Visible spectrophotometer, portable spectrophotometer (PiCOEXPLORER) and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The validation methods consist of determination of linearity, sensitivity, limit of detection and limit of quantification. The results showed that the validation methods of ICP-AES were better than PiCOEXPLORER and UV-Vis spectrophotometer. Based on t-test, it was obtained that the result of Cr(VI) analyses with the comparison of UV-Vis and PiCOEXPLORER, ICP-AES and PiCOEXPLORER, and UV-Vis and ICP-AES; there were no significant difference (tcount |
| 37. | Takayuki Isayama, Yusuke Hasuo, Tomoaki Taniguchi, Kinichi Morita, Hitoshi Mizuguchi, Hiroaki Yoshioka, Yuji Oki, Development Multiple Scattering Colorimetric Spectroscopy for Mobile Metal Trace Detection on Silicone Optical Technology, PITTCON 2020, 2020.03. |
| 38. | Yuta Nakashima, Yoshitaka Nakanishi, Kensaku Kawakami, Soichiro Fukuyama, Mami Akaike, Chacriya Malasuk, Kinichi Morita, Yuji Oki, Kosuke Tashiro, Satoru Kuhara, Real-time Monitoring of Cell Culture using a Microplate Reader Mountable in Incubator, PITTCON 2020, 2020.03, This paper presents that an incubator mountable 96 channel microplate reader for real-time monitoring of cell culture condition during cultivation. Real-time monitoring of the conditions of cultured cells are very important for maintaining and controlling the cell multiplication and the cell differentiation. We previously developed the 24 channel microplate reader for monitoring the culture cells in clean bench using a silicone optical technology (SOT) based spatial filter [1]. SOT is also previously proposed technology by us and can obtain excellent noise reduction effect [2]. The fabricated 24 channel microplate reader achieved the real-time monitoring in clean bench, however, this device was not able to monitor the cellular behavior in the incubator because the light sources, sensors, and electric circuits were not suitable in the high humidity environment. The presented 96 channel microplate reader consists of a SOT spatial filter, 96 light sources, and 96 sensors, was sealed against water for preventing the high humidity. The light source part and sensor part are covered with COP plate that has high optical properties and transparency for maintaining light transmission from the light source to the sensor. The fabricated 96 channel plate reader permits the real-time each well monitoring individually during cultivation in the incubator. As a results of methylene blue absorbance measuring using the fabricated 96 channel plate reader, the absorbance was able to be detected according to the methylene blue concentration. Also, pH of the culture medium was successfully detected as color changes. Moreover, we demonstrated that the condition of the individual cell culture medium in the incubator can be evaluated as absorbance changes in real-time. We would like to discuss these results. [1] Y. Nakashima, et al., Review of Scientific Instruments 90, 035106, 2019. [2] H. Nomada, et al., Talanta 166, 428-432, 2017.. |
| 39. | K. T. Abdul Nasir, Yuya Mikami, Taku Takagishi, Hiroaki Yoshioka, Rui Yatabe, Nilesh J. Vasa, Yuji Oki, Mode shift by absorption of avidin coated on biotinylated microdisk laser printed by ink-jet technique, レーザー学会第540回研究会「有機コヒーレントフォトニクス」, 2019.12. |
| 40. | Yuji Oki, Kinichi Morita, New concept for mobile and compact optical measurement by Silicone Optical Technology, Bio4Apps 2019, 2019.12. |
| 41. | Junfeng Zhu, Chenxi Zhao, Ryo Sakai, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Optimization of spectral performance of CaF2-PDMS filtering material for DNA/protein measurement, Bio4Apps 2019, 2019.12. |
| 42. | Chacriya Malasuk, Keisuke Nakakubo, Ryoichi Ishimatsu, Yuta Nakashima, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Compact and on-demand 3D-printed optical device based on silicone optical technology (SOT) for on-site measurement: Application to flow injection analysis, REVIEW OF SCIENTIFIC INSTRUMENTS, 10.1063/1.5118812, 90, 10, 2019.10. |
| 43. | K. T. Abdul Nasir, Cong Chen, Yuya Mikami, Taku Takagishi, Hiroaki Yoshioka, Motonobu Matsuyama, Naoya Nishimura, Nilesh J. Vasa, Yuji Oki, Lasing characteristics of a pyrromethene597-doped microdisk laser fabricated by the ink-jet printing method, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.7567/1347-4065/ab1e3c, 58, 2019.08, A microdisk laser based on the fluorinated hyper branched polymer FC-V-50 was fabricated on an FEP (fluorinated ethylene propylene) substrate with the use of the ink-jet printing method. Pyrromethene597 doped 10 wt.% FC-V-50 solution in ethanol was used for the fabrication of a microdisk laser. The FC-V-50 polymer is characterized by a carboxyl functional group, which can be activated and attached to an amine group found in biomolecules. Based on the lasing characteristics, it is found that the microdisk laser has a relatively low lasing threshold of 34.51 mu J mm(-2) and a reasonable Q factor of 7.52 x 10(3) at 586.59 nm. Therefore, the microdisk can be used for biosensing. The root mean square (RMS) of the surface roughness of the microdisk was estimated to be 6.2 nm. The surface roughness results scattering losses and limits the Q factor. This work reports the first demonstration of a microdisk laser based on FC-V-50 for biosensing applications. (C) 2019 The Japan Society of Applied Physics. |
| 44. | K. T. Abdul Nasir, Cong Chen, Yuya Mikami, Taku Takagishi, Hiroaki Yoshioka, Motonobu Matsuyama, Naoya Nishimura, Nilesh J. Vasa, Yuji Oki, Lasing characteristics of a pyrromethene597-doped microdisk laser fabricated by the ink-jet printing method, Japanese Journal of Applied Physics, Volume 58, Number SJ, 2019.07. |
| 45. | Lei Wan, Cong Chen, Junfeng Zhu, K T Abdul Nasir, Qingyu Cui, Zhenshi Chen, Hiroaki Yoshioka, Weiping Liu, Yuji Oki, Zhaohui Li, Changes in optical characteristics induced by polymer blending in printed colloidal quantum dots microlasers., Optics express, 10.1364/OE.27.019615, 27, 14, 19615-19623, 2019.07, On-chip microlasers are desirable to meet the different control requirements and unique demands in different application scenarios. In this work, we obtained the on-chip microlaser by printing pixelated CdSe/ZnS colloidal quantum dots (CQDs), incorporating the quantum dot self-assembly mechanism and the external cavity-free configuration. The spectral purity of the microlaser can be significantly improved by slightly blending polymer into the CQD matrix. The quasitoroid profile was gradually changed to microdisks as the polystyrene (PS) concentration increased from 0 wt.% to 10 wt.%. Specially, when the PS solution varied from 0 wt.% to 1 wt.%, the lasing threshold of 1.4 μJ/mm2 was increased up to 14 μJ/mm2, meanwhile the emission wavelength range showed a 25 nm blue-shift approximately. The easy printing technologies and the low-cost polymer blending method employed in the obtained microlasers will further facilitate the development of printing photonics and electronics, especially in the high-performance microlaser displays and high-precision sensors.. |
| 46. | Lei Wan, Cong Chen, Junfeng Zhu, K. T. Abdul Nasir, Qingyu Cui, Zhenshi Chen, Hiroaki Yoshioka, Weiping Liu, Yuji Oki, Zhaohui Li, Changes in optical characteristics induced by polymer blending in printed colloidal quantum dots microlasers, OPTICS EXPRESS, 10.1364/OE.27.019615, 27, 14, 19615-19623, 2019.07, On-chip microlasers are desirable to meet the different control requirements and unique demands in different application scenarios. In this work, we obtained the on-chip microlaser by printing pixelated CdSe/ZnS colloidal quantum dots (CQDs), incorporating the quantum dot self-assembly mechanism and the external cavity-free configuration. The spectral purity of the microlaser can be significantly improved by slightly blending polymer into the CQD matrix. The quasitoroid profile was gradually changed to microdisks as the polystyrene (PS) concentration increased from 0 wt.% to 10 wt.%. Specially, when the PS solution varied from 0 wt.% to 1 wt.%, the lasing threshold of 1.4 mu J/mm(2) was increased up to 14 mu J/mm(2), meanwhile the emission wavelength range showed a 25 nm blue-shift approximately. The easy printing technologies and the low-cost polymer blending method employed in the obtained microlasers will further facilitate the development of printing photonics and electronics, especially in the high-performance microlaser displays and high-precision sensors. (c) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. |
| 47. | Taku Takagishi, Hiroaki Yoshioka, Yuya Mikami, Naoya Nishimura, Yuji Oki, Improvement of lasing threshold of ink-jet printed polymeric microdisk cavity by precise controlled wet etching, 2019 Conference on Lasers and Electro-Optics, CLEO 2019 2019 Conference on Lasers and Electro-Optics, CLEO 2019 - Proceedings, 10.23919/CLEO.2019.8749640, 2019.05, With well-controlled wet etching process, under-cut structure of ink-jet printed microdisk was successfully formed and we succeeded in lowering the lasing threshold by 10 times, compared with the one on a substrate.. |
| 48. | Chacriya Malasuk, Keisuke Nakakubo, Shota Tsuru, Hiroaki Yoshioka, Kinichi Morita, Yuta Nakashima, Yuji Oki, Silicone Optical Technology Quasi Spatial Filter and its Application for Multichannel Absorption Analysis, 2018 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2018, 2019.04, Quasi spatial filter was purposed based on silicone optical technology (SOT). A simple structure as coaxial combination of a transparent polydimethylsiloxane (PDMS) core and carbon/PDMS clad was developed and then applied for multichannel absorption analysis.. |
| 49. | Chacriya Malasuk, Keisuke Nakakubo, Shota Tsuru, Hiroaki Yoshioka, Kinichi Morita, Yuta Nakashima, Yuji Oki, Silicone Optical Technology: Quasi Spatial Filter and its Application for Multichannel Absorption Analysis, 2018 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2018, Part F113-CLEOPR 2018, 2019.04, © 2018 OSA. Quasi spatial filter was purposed based on silicone optical technology (SOT). A simple structure as coaxial combination of a transparent polydimethylsiloxane (PDMS) core and carbon/PDMS clad was developed and then applied for multichannel absorption analysis.. |
| 50. | Yuta Nakashima, Masaki Kounoura, Chacriya Malasuk, Keisuke Nakakubo, Naho Watanabe, S. Iwata, Kinichi Morita, Yuji Oki, Satoru Kuhara, Kosuke Tashiro, Yoshitaka Nakanishi, Continuous cell culture monitoring using a compact microplate reader with a silicone optical technology-based spatial filter, REVIEW OF SCIENTIFIC INSTRUMENTS, 10.1063/1.5054824, 90, 3, 2019.03. |
| 51. | Harunobu Takeda, Michika Takeda, Hiroaki Yoshioka, Hiroaki Minamide, Yuji Oki, Chihaya Adachi, Fluorescence lifetime elongation of thermally activated delayed fluorescence 4CzIPN molecules with encapsulation into zeolitic imidazole frameworks ZIF-11, Optical Materials Express, 10.1364/OME.9.001150, 9, 3, 1150-1160, 2019.03, Encapsulation of fluorescent directives "thermally activated delayed fluorescence" molecules into a zeolitic imidazole frameworks was proposed, and 4CzIPN molecules were successfully encapsulated into ZIF-11 pores by one step process with a loading efficiency of 0.064 of the proportion of 4CzIPN/ZIF-11. Some Spectroscopic studies such as XRD, UV-Vis, FTIR, THz-TDS and time resolved streak measurement, and the suppression of intramolecular vibrational, rotational and librational motions of 4CzIPN molecules were confirmed. Interestingly, the florescence lifetime of 4CzIPN was considerably elongated from 2.37 ns to 14.8 ns, while the phosphorescence lifetime became a little bit short from 2.15 μs to 1.65 μs. The lifetime differences was thought to be due to the suppression of the 4CzIPN molecules' motion by the close ZIF-11 frameworks that affected the reverse intersystem crossing.. |
| 52. | Junfeng Zhu, Keisuke Nakakubo, Yuya Mikami, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Investigation and modeling of UV band-passfiltering white compound materials for potting or embedding in micro-optical applications, Optical Materials Express, 10.1364/OME.9.001002, 9, 3, 1002-1014, 2019.03, A novel white compound material with spectral band pass filtering was proposed and demonstrated in the UV region for wavelengths smaller than 310 nm. This compound material can be obtained by dispersing CaF 2 in polydimethylsiloxane (PDMS). Refractive index matching (RIM) of the compound material resulted in transmittance of up to 80% at RIM wavelength. In no-RIM wavelength region, refractive index difference about 0.005 could result in transmittance of down to 30% due to intense Rayleigh isotropic scattering. A good reproducibility of the transparent wavelength can be obtained with the specific CaF 2 particle and PDMS matrix in this study. Meanwhile, simple calculation based on Rayleigh- Gans-Debye approximation [J. Am. Ceram. Soc. 86(3), 480-486 (2003)] in the soft diffusion model can explain the CaF 2 : PDMS compound film transmittance spectrum in the UV region, and the bandwidth narrowing condition.. |
| 53. | Yuta Nakashima, Masaki Kounoura, Chacriya Malasuk, Keisuke Nakakubo, Naho Watanabe, Sae Iwata, Kinichi Morita, Yuji Oki, Satoru Kuhara, Kosuke Tashiro, Yoshitaka Nakanishi, Continuous cell culture monitoring using a compact microplate reader with a silicone optical technology-based spatial filter, Review of Scientific Instruments, 10.1063/1.5054824, 90, 3, 035106, 2019.03. |
| 54. | Harunobu Takeda, Michika Takeda, Hiroaki Yoshioka, Hiroaki Minamide, Yuji Oki, Chihaya Adachi, Fluorescence lifetime elongation of thermally activated delayed fluorescence 4CzIPN molecules with encapsulation into zeolitic imidazole frameworks ZIF-11, OPTICAL MATERIALS EXPRESS, 10.1364/OME.9.001150, 9, 3, 1150-1160, 2019.03, Encapsulation of fluorescent directives "thermally activated delayed fluorescence" molecules into a zeolitic imidazole frameworks was proposed, and 4CzIPN molecules were successfully encapsulated into ZIF-11 pores by one step process with a loading efficiency of 0.064 of the proportion of 4CzIPN/ZIF-11. Some Spectroscopic studies such as XRD, UV-Vis, FTIR, THz-TDS and time resolved streak measurement, and the suppression of intramolecular vibrational, rotational and librational motions of 4CzIPN molecules were confirmed. Interestingly, the florescence lifetime of 4CzIPN was considerably elongated from 2.37 ns to 14.8 ns, while the phosphorescence lifetime became a little bit short from 2.15 mu s to 1.65 mu s. The lifetime differences was thought to be due to the suppression of the 4CzIPN molecules' motion by the close ZIF-11 frameworks that affected the reverse intersystem crossing. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. |
| 55. | Junfeng Zhu, Keisuke Nakakubo, Yuya Mikami, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Investigation and modeling of UV band-pass-filtering white compound materials for potting or embedding in micro-optical applications, OPTICAL MATERIALS EXPRESS, 10.1364/OME.9.001002, 9, 3, 1002-1014, 2019.03, A novel white compound material with spectral band pass filtering was proposed and demonstrated in the UV region for wavelengths smaller than 310 nm. This compound material can be obtained by dispersing CaF2 in polydimethylsiloxane (PDMS). Refractive index matching (RIM) of the compound material resulted in transmittance of up to 80% at RIM wavelength. In no-RIM wavelength region, refractive index difference about 0.005 could result in transmittance of down to 30% due to intense Rayleigh isotropic scattering. A good reproducibility of the transparent wavelength can be obtained with the specific CaF, particle and PDMS matrix in this study. Meanwhile, simple calculation based on RayleighGans-Debye approximation |
| 56. | SAKAI RYO, Nakakubo Keisuke, Chacriya Malasuk, Hiroaki Yoshioka, Kinichi Morita, Yuta Nakashima, Yuji Oki, Compact and Multiplexed Absorptionmeter with Newly Developed Arrayed Quasi Spatial Filter Integrated for Microplate Analysis, PITTCON 2019, 2019.03. |
| 57. | JUNFENG ZHU, Yusuke Hasuo, Keisuke Nakakubo, Yuya Mikami, Hiroaki Yoshioka, Kinichi Morita, Oki Yuji, Development of Compact Optical System based on Transparent / Translucent Filters in UV Region, PITTCON 2019, 2019.03. |
| 58. | YUTA NAKASHIMA, Masaki Kounoura, Chacriya Malasuk, Keisuke Nakakubo, Naho Watanabe, Kinichi Morita, Yuji Oki, Satoru Kuhara, Kosuke Tashiro, Yoshitaka Nakanishi, Development of a Compact Microplate Reader Using a Silicone Optical Technology-Based Spatial Filter for Real-Time Monitoring of Cell Culture Condition During Cultivation, PITTCON 2019, 2019.03. |
| 59. | Cong Chen, Jin Yuan, Lei Wan, Hengky Chandrahalim, Zhenshi Chen, Naoya Nishimura, Harunobu Takeda, Hiroaki Yoshioka, Weiping Liu, Yuji Oki, Xudong Fan, Zhaohui Li, Demonstration of on-chip quantum dot microcavity lasers in a molecularly engineered annular groove, Optics Letters, 10.1364/OL.44.000495, 44, 3, 495-498, 2019.02, The on-chip quantum dot (QD) microcavity laser engineered on an annular groove made of fused silica was demonstrated based on the external quasi-cavity configuration. By incorporating an appropriate dose of polymer into QD film, the spectral purity of the lasing spectrum was significantly enhanced. In contrast to the dye microcavity laser embedded on the same trench profile, a QD laser possesses a lifetime that is over 10 times longer. We have introduced a unique two-step quantum gain deposition process that has remarkably reduced the wavelength drifts of laser emissions in an aqueous environment by approximately 400%. The reconfigurable cavity platform in combination with an appropriately engineered quantum gain medium embedded onto it promises to enable photostable chip-scale coherent light sources for various photonic, chemical, and biochemical sensing applications.. |
| 60. | Cong Chen, Jin Yuan, Lei Wan, Hengky Chandrahalim, Zhenshi Chen, Naoya Nishimura, Harunobu Takeda, Hiroaki Yoshioka, Weiping Liu, Yuji Oki, Xudong Fan, Zhaohui Li, Demonstration of on-chip quantum dot microcavity lasers in a molecularly engineered annular groove., Optics letters, 10.1364/OL.44.000495, 44, 3, 495-498, 2019.02, The on-chip quantum dot (QD) microcavity laser engineered on an annular groove made of fused silica was demonstrated based on the external quasi-cavity configuration. By incorporating an appropriate dose of polymer into QD film, the spectral purity of the lasing spectrum was significantly enhanced. In contrast to the dye microcavity laser embedded on the same trench profile, a QD laser possesses a lifetime that is over 10 times longer. We have introduced a unique two-step quantum gain deposition process that has remarkably reduced the wavelength drifts of laser emissions in an aqueous environment by approximately 400%. The reconfigurable cavity platform in combination with an appropriately engineered quantum gain medium embedded onto it promises to enable photostable chip-scale coherent light sources for various photonic, chemical, and biochemical sensing applications.. |
| 61. | Cong Chen, Jin Yuan, Lei Wan, Hengky Chandrahalim, Zhenshi Chen, Naoya Nishimura, Harunobu Takeda, Hiroaki Yoshioka, Weiping Liu, Yuji Oki, Xudong Fan, Zhaohui Li, Demonstration of on-chip quantum dot microcavity lasers in a molecularly engineered annular groove, OPTICS LETTERS, 10.1364/OL.44.000495, 44, 3, 495-498, 2019.02, The on-chip quantum dot (QD) microcavity laser engineered on an annular groove made of fused silica was demonstrated based on the external quasi-cavity configuration. By incorporating an appropriate dose of polymer into QD film, the spectral purity of the lasing spectrum was significantly enhanced. In contrast to the dye microcavity laser embedded on the same trench profile, a QD laser possesses a lifetime that is over 10 times longer. We have introduced a unique two-step quantum gain deposition process that has remarkably reduced the wavelength drifts of laser emissions in an aqueous environment by approximately 400%. The reconfigurable cavity platform in combination with an appropriately engineered quantum gain medium embedded onto it promises to enable photostable chip-scale coherent light sources for various photonic, chemical, and biochemial sensing applications. (C) 2019 Optical Society of America. |
| 62. | Suherman, Nicko Audio Haryanto, Endan Tri Wahyuni, Miftahul Ilmi, Kinichi Morita, Yuji Oki, Carbon Dots Modification for Escherichia coli Detection: Variation of Colistin Sulphate Concentration, ORIENTAL JOURNAL OF CHEMISTRY, 10.13005/ojc/350105, 35, 1, 49-55, 2019.01, [URL]. |
| 63. | Chacriya Malasuk, Keisuke Nakakubo, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, 3D printing optical devices based on silicone optical technology (SOT) and its application on analytical chemistry, Optical Components and Materials XVI 2019 Optical Components and Materials XVI, 10.1117/12.2508677, 2019.01, Mold free and additive embedding of quasi-spatial filter (QSF) for simple optical detection was proposed. With a concept of "silicone optical technology (SOT)" we proposed, fully flexible and digitally fabrication of compact optical module for flow-injection analysis (FIA) was demonstrated. It was attained by combining silicone 3D printed rough-frame and injecting and coating method for embedding SOT-QSF that can trap unexpected light signal as tilted incidence. SOT-QSF's coaxial cylindrical structure of PDMS core and carbon-dispersed-PDMS clad was fabricated by injecting and coating method. The coating properties and optical trapping performance was evaluated. These embedding techniques and method developments will be useful for on-site applications with general FIA researches and for rapid on-demand-fabrication based on researcher's idea.. |
| 64. | Soichiro Ryu, Hiroaki Yoshioka, Cong Chen, Kei Yasui, Yuji Oki, High-Q printable polymer microdisk without etching, 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015 Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015, 2019.01. |
| 65. | Taku Takagishi, Hiroaki Yoshioka, Yuya Mikami, Naoya Nishimura, Yuji Oki, Improvement of lasing threshold of ink-jet printed polymeric microdisk cavity by precise controlled wet etching, CLEO: Science and Innovations, CLEO_SI 2019 CLEO Science and Innovations, CLEO_SI 2019, 10.1364/CLEO_SI.2019.SM2O.5, 2019.01, With well-controlled wet etching process, under-cut structure of ink-jet printed microdisk was successfully formed and we succeeded in lowering the lasing threshold by 10 times, compared with the one on a substrate.. |
| 66. | K. T.Abdul Nasir, Cong Chen, Yuya Mikami, Taku Takagishi, Hiroaki Yoshioka, Motonobu Matsuyama, Naoya Nishimura, Nilesh J. Vasa, Yuji Oki, Lasing characteristics of a pyrromethene597-doped microdisk laser fabricated by the ink-jet printing method, Japanese Journal of Applied Physics, 10.7567/1347-4065/ab1e3c, 58, SJ, 2019.01, A microdisk laser based on the fluorinated hyper branched polymer FC-V-50 was fabricated on an FEP (fluorinated ethylene propylene) substrate with the use of the ink-jet printing method. Pyrromethene597 doped 10 wt.% FC-V-50 solution in ethanol was used for the fabrication of a microdisk laser. The FC-V-50 polymer is characterized by a carboxyl functional group, which can be activated and attached to an amine group found in biomolecules. Based on the lasing characteristics, it is found that the microdisk laser has a relatively low lasing threshold of 34.51 μJ mm-2 and a reasonable Q factor of 7.52 × 103 at 586.59 nm. Therefore, the microdisk can be used for biosensing. The root mean square (RMS) of the surface roughness of the microdisk was estimated to be 6.2 nm. The surface roughness results scattering losses and limits the Q factor. This work reports the first demonstration of a microdisk laser based on FC-V-50 for biosensing applications.. |
| 67. | Lei Wan, Cong Chen, Junfeng Zhu, K. T.Abdul Nasir, Qingyu Cui, Zhenshi Chen, Hiroaki Yoshioka, Weiping Liu, Yuji Oki, Zhaohui Li, Changes in optical characteristics induced by polymer blending in printed colloidal quantum dots microlasers, Optics Letters, 10.1364/OE.27.019615, 27, 14, 19615-19623, 2019.01, On-chip microlasers are desirable to meet the different control requirements and unique demands in different application scenarios. In this work, we obtained the on-chip microlaser by printing pixelated CdSe/ZnS colloidal quantum dots (CQDs), incorporating the quantum dot self-assembly mechanism and the external cavity-free configuration. The spectral purity of the microlaser can be significantly improved by slightly blending polymer into the CQD matrix. The quasitoroid profile was gradually changed to microdisks as the polystyrene (PS) concentration increased from 0 wt.% to 10 wt.%. Specially, when the PS solution varied from 0 wt.% to 1 wt.%, the lasing threshold of 1.4 μJ/mm2 was increased up to 14 μJ/mm2, meanwhile the emission wavelength range showed a 25 nm blue-shift approximately. The easy printing technologies and the low-cost polymer blending method employed in the obtained microlasers will further facilitate the development of printing photonics and electronics, especially in the high-performance microlaser displays and high-precision sensors.. |
| 68. | Suherman, NICKO AUDIO HARYANTO, ENDANG TRI WAHYUNI, MIFTAHUL ILMI, KINICHI MORITA, Yuji Oki, Carbon Dots Modification for Escherichia coli Detection: Variation of Colistin Sulphate Concentration, Oriental Journal of Chemistry, 10.13005/350105, 35, 1, 49-55, 2019, Escherichia coli bacteria widely recognize as a major treatment in water quality as diarrhea disease becoming one of leading causes of mortality worldwide. Carbon dots (CDs) modification study for detection of E. coli with the variation of colistin sulphate concentration has been conducted. The purpose of this research is to evaluate the effect of colistin sulphate concentration variation on fluorescence intensity for detecting E. coli bacteria in water samples. This study started by synthesizing CDs and CDs colistin variation concentrations of 1.0; 1.5; 2.0 and 2.5 mmol through carbonization of ammonium citrate and the addition of colistin. All precursors are characterized by using FT-IR. Morphological forms were evaluated with scanning emission microscopy (SEM) and transmission electron microscopy (TEM). CDs and CDs colistin solutions were measured their spectras with a UV-Vis spectrophotometer. Each of these CDs colistin was determined at the excitation wavelength ranges of 310-450 nm using a spectrofluorophotometer. Subsequently, CDs colistin was used for bacterial detection in samples with variation in E. coli bacteria concentration, thus analyzed by spectrofluorophotometer with an optimum excitation wavelength. The results showed that the highest intensity of fluorescence on CDs colistin occurred at the wavelength excitation of 360 nm. CDs colistin with the variation of colistin concentration 2.5 mmol revealed the highest fluorescence intensity. For the detection of E. coli, all CDs colistin produced the same trends of fluorescence spectra as the higher concentration of E. coli in the samples produced the higher intensity of emission.. |
| 69. | Hiroaki Yoshioka, Shintaro Mitsui, Yuji Oki, Lasing from Printable Organic-Inorganic Microdisk Cavity with Mixed Doping of Laser Dye and ZnO, 2018 European Conference on Optical Communication, ECOC 2018 2018 European Conference on Optical Communication, ECOC 2018, 10.1109/ECOC.2018.8535487, 2018.11, We have experimentally demonstrated a fabrication and WGM lasing of organic-inorganic microdisk mixed with laser dye and ZnO by the ink-jet printing without co-doping binding polymer for cavity host. This is the first demonstration of binder-free organic-inorganic hybrid microdisk lasers.. |
| 70. | Taku Takagishi, Hiroaki Yoshioka, Shintaro Mitsui, Yuya Mikami, Naoya Nishimura, Yuji Oki, Highly Transparent Organic Microdisk Cavity in Visible Range by the Ink-jet Printing Method, 2018 Conference on Lasers and Electro-Optics, CLEO 2018 2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings, 2018.08, We experimentally demonstrated the fabrication and the fundamental lasing evaluation of a printed microdisk cavity by focusing on a fluorinated spherical polymer FZ-001 to achieve a microdisk with small absorption loss in the visible range.. |
| 71. | Keisuke Nakakubo, Junfeng Zhu, Yuya Mikami, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Novel spectroscopic transparent/scattering material for 260/280nm ultraviolet optical detection, 2018 Conference on Lasers and Electro-Optics, CLEO 2018 2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings, 2018.08, Novel type of wavelength filter was proposed and demonstrated. Polydimethylsiloxane was mixed with CaF2 particles. This scattering material of 30wt% provided transparency at specified wavelength of 259 nm and 278nm.. |
| 72. | Keisuke Nakakubo, Hiroaki Nomada, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, On-demand lens fabrication by liquid phase molding with gallium and Polydimethylsiloxane, 2018 Conference on Lasers and Electro-Optics, CLEO 2018 2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings, 2018.08, A new on-demand lens fabrication with gallium molding was proposed and demonstrated. A convex and concave surface of liquid gallium is transferred to Polydimethylsiloxane. The curvature can be controlled between ±0.37 mm-1.. |
| 73. | Lei Wan, Hengky Chandrahalim, Jian Zhou, Zhaohui Li, Cong Chen, Sangha Cho, Hui Zhang, Ting Mei, Huiping Tian, Yuji Oki, Naoya Nishimura, Xudong Fan, L. Jay Guo, Demonstration of versatile whispering-gallery micro-lasers for remote refractive index sensing, Optics Express, 10.1364/OE.26.005800, 26, 5, 5800-5809, 2018.03, We developed chip-scale remote refractive index sensors based on Rhodamine 6G (R6G)-doped polymer micro-ring lasers. The chemical, temperature, and mechanical sturdiness of the fused-silica host guaranteed a flexible deployment of dye-doped polymers for refractive index sensing. The introduction of the dye as gain medium demonstrated the feasibility of remote sensing based on the free-space optics measurement setup. Compared to the R6G-doped TZ-001, the lasing behavior of R6G-doped SU-8 polymer micro-ring laser under an aqueous environment had a narrower spectrum linewidth, producing the minimum detectable refractive index change of 4 × 10−4 RIU. The maximum bulk refractive index sensitivity (BRIS) of 75 nm/RIU was obtained for SU-8 laser-based refractive index sensors. The economical, rapid, and simple realization of polymeric micro-scale whispering-gallery-mode (WGM) laser-based refractive index sensors will further expand pathways of static and dynamic remote environmental, chemical, biological, and bio-chemical sensing.. |
| 74. | Yuya Mikami, Hiroaki Yoshioka, Soichiro Ryu, Naoya Nishimura, Yuji Oki, Organic-inorganic hybrid microdisk laser with dye and silica mixed doping prepared by ink-jet printing method, Optics Express, 10.1364/OE.26.007140, 26, 6, 7140-7147, 2018.03, We developed an ink-jet printing method for fabricating inorganic microdisks at room temperature, which is much lower than the melting point of solid-state inorganic oxide, and have fabricated an organic-inorganic hybrid microdisk laser. Silica was used as the inorganic disk material, and microdisk-shaped aggregates were formed by the ink-jet printing method using a solution in which nanosilica particles were dispersed in propylene glycol monomethylether (PGME) solvent. Then, a microdisk capable of laser oscillation was also prepared by preliminarily adding the laser dye rhodamine 6G to the ink to form a mixed organic material. The structural evaluation of the printed microdisk was first conducted using an optical microscope, a scanning electron microscope (SEM), and an atomic force microscope (AFM). The results of laser oscillation evaluation by optical excitation showed that the printed microdisk sufficiently functions as an optical resonator with a low optical loss. In these evaluations, excellent values such as a surface roughness of 5.83 nm from root mean square (R. M. S.) which is one forth smaller than the particle diameter, and a laser oscillation threshold of 4.76 μJ/mm2 at a wavelength of 601.4 nm were obtained. To the best of our knowledge, this is the first time that an inorganic microdisk has been fabricated at room temperature to realize an organic-inorganic hybrid microdisk laser.. |
| 75. | Lei Wan, Hengky Chandrahalim, Jian Zhou, Zhaohui Li, Cong Chen, Sangha Cho, Hui Zhang, Ting Mei, Huiping Tian, Yuji Oki, Naoya Nishimura, Xudong Fan, L. Jay Guo, Demonstration of versatile whispering-gallery micro-lasers for remote refractive index sensing, Optics Express, 10.1364/OE.26.005800, 26, 5, 5800-5809, 2018.03, We developed chip-scale remote refractive index sensors based on Rhodamine 6G (R6G)-doped polymer micro-ring lasers. The chemical, temperature, and mechanical sturdiness of the fused-silica host guaranteed a flexible deployment of dye-doped polymers for refractive index sensing. The introduction of the dye as gain medium demonstrated the feasibility of remote sensing based on the free-space optics measurement setup. Compared to the R6G-doped TZ-001, the lasing behavior of R6G-doped SU-8 polymer micro-ring laser under an aqueous environment had a narrower spectrum linewidth, producing the minimum detectable refractive index change of 4 × 10−4 RIU. The maximum bulk refractive index sensitivity (BRIS) of 75 nm/RIU was obtained for SU-8 laser-based refractive index sensors. The economical, rapid, and simple realization of polymeric micro-scale whispering-gallery-mode (WGM) laser-based refractive index sensors will further expand pathways of static and dynamic remote environmental, chemical, biological, and bio-chemical sensing.. |
| 76. | Yuya Mikami, Hiroaki Yoshioka, Soichiro Ryu, Naoya Nishimura, Yuji Oki, Organic-inorganic hybrid microdisk laser with dye and silica mixed doping prepared by ink-jet printing method, OPTICS EXPRESS, 10.1364/OE.26.007140, 26, 6, 7140-7147, 2018.03, We developed an ink-jet printing method for fabricating inorganic microdisks at room temperature, which is much lower than the melting point of solid-state inorganic oxide, and have fabricated an organic-inorganic hybrid microdisk laser. Silica was used as the inorganic disk material, and microdisk-shaped aggregates were formed by the ink-jet printing method using a solution in which nanosilica particles were dispersed in propylene glycol monomethylether (PGME) solvent. Then, a microdisk capable of laser oscillation was also prepared by preliminarily adding the laser dye rhodamine 6G to the ink to form a mixed organic material. The structural evaluation of the printed microdisk was first conducted using an optical microscope, a scanning electron microscope (SEM), and an atomic force microscope (AFM). The results of laser oscillation evaluation by optical excitation showed that the printed microdisk sufficiently functions as an optical resonator with a low optical loss. In these evaluations, excellent values such as a surface roughness of 5.83 nm from root mean square (R. M. S.) which is one forth smaller than the particle diameter, and a laser oscillation threshold of 4.76 mu J/mm(2) at a wavelength of 601.4 nm were obtained. To the best of our knowledge, this is the first time that an inorganic microdisk has been fabricated at room temperature to realize an organic-inorganic hybrid microdisk laser. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. |
| 77. | Cong Chen, Lei Wan, Hengky Chandrahalim, Jian Zhou, Hui Zhang, Sangha Cho, Ting Mei, Hiroaki Yoshioka, Huiping Tian, Naoya Nishimura, Xudong Fan, L. Jay Guo, Yuji Oki, Effects of edge inclination angles on whispering-gallery modes in printable wedge microdisk lasers, Optics Express, 10.1364/OE.26.000233, 26, 1, 233-241, 2018.01, The ink-jet technique was developed to print the wedge polymer microdisk lasers. The characterization of these lasers was implemented using a free-space optics measurement setup. It was found that disks of larger edge inclination angles have a larger free spectral range (FSR) and a lower resonance wavelength difference between the fundamental transverse electric (TE) and transverse magnetic (TM) whispering-gallery modes (WGMs). This behavior was also confirmed with simulations based on the modified Oxborrow’s model with perfectly matched layers (PMLs), which was adopted to accurately calculate the eigenfrequencies, electric field distributions, and quality parameters of modes in the axisymmetric microdisk resonators. Combined with the nearly equivalent quality factor (Q-factor) and finesse factor (F-factor) variations, the correlations between the TE and left adjacent TM modes were theoretically demonstrated. When the edge inclination angle is varied, the distinguishable mode distribution facilitates the precise estimation of a resonance wavelength shift. Therefore, the flexible and efficient nature of wedge polymer microdisk lasers extends their potential applications in precision sensing technology.. |
| 78. | Taku Takagishi, Hiroaki Yoshioka, Shintaro Mitsui, Yuya Mikami, Naoya Nishimura, Yuji Oki, Highly transparent organic microdisk cavity in visible range by the ink-jet printing method, CLEO: Applications and Technology, CLEO_AT 2018 CLEO Applications and Technology, CLEO_AT 2018, 10.1364/CLEO_AT.2018.JTh2A.81, 2018.01, We experimentally demonstrated the fabrication and the fundamental lasing evaluation of a printed microdisk cavity by focusing on a fluorinated spherical polymer FZ-001 to achieve a microdisk with small absorption loss in the visible range.. |
| 79. | Keisuke Nakakubo, Junfeng Zhu, Yuya Mikami, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Novel spectroscopic transparent/scattering material for 260/280nm ultraviolet optical detection, CLEO: Applications and Technology, CLEO_AT 2018 CLEO Applications and Technology, CLEO_AT 2018, 10.1364/CLEO_AT.2018.JTh2A.86, 2018.01, Novel type of wavelength filter was proposed and demonstrated. Polydimethylsiloxane was mixed with CaF2 particles. This scattering material of 30wt% provided transparency at specified wavelength of 259 nm and 278nm.. |
| 80. | Keisuke Nakakubo, Hiroaki Nomada, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, On-demand lens fabrication by liquid phase molding with gallium and Polydimethylsilo, CLEO: Science and Innovations, CLEO_SI 2018 CLEO Science and Innovations, CLEO_SI 2018, 10.1364/CLEO_SI.2018.STh1I.7, 2018.01, A new on-demand lens fabrication with gallium molding was proposed and demonstrated. A convex and concave surface of liquid gallium is transferred to Polydimethylsiloxane. The curvature can be controlled between ±0.37 mm-1.. |
| 81. | Chacriya Malasuk, Keisuke Nakakubo, Shota Tsuru, Hiroaki Yoshioka, Kinichi Morita, Yuta Nakashima, Yuji Oki, Silicone optical technology Quasi spatial filter and its application for multichannel absorption analysis, Conference on Lasers and Electro-Optics/Pacific Rim, CLEOPR 2018 Conference on Lasers and Electro-Optics/Pacific Rim, CLEOPR 2018, 2018.01, Quasi spatial filter was purposed based on silicone optical technology (SOT). A simple structure as coaxial combination of a transparent polydimethylsiloxane (PDMS) core and carbon/PDMS clad was developed and then applied for multichannel absorption analysis.. |
| 82. | Cong Chen, Lei Wan, Hengky Chandrahalim, Jian Zhou, Hui Zhang, Sangha Cho, Ting Mei, Hiroaki Yoshioka, Huiping Tian, Naoya Nishimura, Xudong Fan, L. Jay Guo, Yuji Oki, Effects of edge inclination angles on whispering-gallery modes in printable wedge microdisk lasers, OPTICS EXPRESS, 10.1364/OE.26.000233, 26, 1, 233-241, 2018.01, The ink-jet technique was developed to print the wedge polymer microdisk lasers. The characterization of these lasers was implemented using a free-space optics measurement setup. It was found that disks of larger edge inclination angles have a larger free spectral range (FSR) and a lower resonance wavelength difference between the fundamental transverse electric (TE) and transverse magnetic (TM) whispering-gallery modes (WGMs). This behavior was also confirmed with simulations based on the modified Oxborrow's model with perfectly matched layers (PMLs), which was adopted to accurately calculate the eigenfrequencies, electric field distributions, and quality parameters of modes in the axisymmetric microdisk resonators. Combined with the nearly equivalent quality factor (Q-factor) and finesse factor (F-factor) variations, the correlations between the TE and left adjacent TM modes were theoretically demonstrated. When the edge inclination angle is varied, the distinguishable mode distribution facilitates the precise estimation of a resonance wavelength shift. Therefore, the flexible and efficient nature of wedge polymer microdisk lasers extends their potential applications in precision sensing technology. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing. |
| 83. | Fabrication and Lasing Evaluation of Fluorinated Spherical Polymer based Microdisk Cavity Printed by Ink-Jet Technique. |
| 84. | Keisuke Nakakubo, Hiroaki Nomada, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Gallium and polydimethylsiloxane molding for self-organized spherical lens surface fabrication, Applied Optics, 10.1364/AO.56.009900, 56, 36, 9900-9906, 2017.12, We present a new fabrication method for optical surfaces using liquid metal molding. Common optical surfaces are fabricated by the polishing of glasses or plastics. By contrast, the fabrication method we propose involves the transfer of a spherical surface of liquid molded metal with silicone rubber. The concept presented in this paper is of a new molding method in which a mold is placed inside. The curvature can be controlled from ∼0.37 mm−1 to −0.37 mm−1 by wetting the liquid metal. An application of this method is to produce on-demand optical elements (e.g., lenses and mirrors).. |
| 85. | Keisuke Nakakubo, Hiroaki Nomada, Hiroaki Yoshioka, Kinichi Morita, Yuji Oki, Gallium and polydimethylsiloxane molding for self-organized spherical lens surface fabrication, APPLIED OPTICS, 10.1364/AO.56.009900, 56, 36, 9900-9906, 2017.12, We present a new fabrication method for optical surfaces using liquid metal molding. Common optical surfaces are fabricated by the polishing of glasses or plastics. By contrast, the fabrication method we propose involves the transfer of a spherical surface of liquid molded metal with silicone rubber. The concept presented in this paper is of a new molding method in which a mold is placed inside. The curvature can be controlled from similar to 0.37 mm(-1) to -0.37 mm(-1) by wetting the liquid metal. An application of this method is to produce on-demand optical elements (e.g., lenses and mirrors). (c) 2017 Optical Society of America. |
| 86. | Hiroaki Yoshioka, Yuya Mikami, Soichiro Ryu, Shintaro Mitsui, Cong Chen, Naoya Nishimura, Yuji Oki, Silica-based inorganic microdisk cavity by the ink-jet printing method, 2017 Conference on Lasers and Electro-Optics, CLEO 2017 2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings, 10.1364/CLEO_SI.2017.JTu5A.119, 2017-January, 1-2, 2017.10, We experimentally succeeded fabrication and WGM lasing of inorganic microdisks by the ink-jet printing method. This silica-based microdisk cavity is the first demonstration in ordinary pressure and temperature among inorganic microdisks.. |
| 87. | Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, L. Jay Guo, Xudong Fan, On-chip, high-sensitivity temperature sensors based on dye-doped solid-state polymer microring lasers, Applied Physics Letters, 10.1063/1.4986825, 111, 6, 2017.08, We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/°C based on a rhodamine 6G (R6G)-doped SU-8 whispering gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 μm height that provided detection sensitivity, and the chemically robust fused-silica microring resonator host platform guaranteed its versatility for investigating different functional polymer materials with different refractive indices. As a proof of concept, a dye-doped hyperbranched polymer (TZ-001) microring laser-based temperature sensor was simultaneously developed on the same host wafer and characterized using a free-space optics measurement setup. Compared to TZ-001, the SU-8 polymer microring laser had a lower lasing threshold and a better photostability. The R6G-doped SU-8 polymer microring laser demonstrated greater adaptability as a high-performance temperature-sensing element. In addition to the sensitivity, the temperature resolutions for the laser-based sensors were also estimated to be 0.13 °C and 0.35 °C, respectively. The rapid and simple implementation of micrometer-sized temperature sensors that operate in the range of 31 - 43 °C enables their potential application in thermometry.. |
| 88. | Takeshi Komino, Yuji Oki, Chihaya Adachi, Dipole orientation analysis without optical simulation application to thermally activated delayed fluorescence emitters doped in host matrix, Scientific Reports, 10.1038/s41598-017-08708-1, 7, 1, 8405, 2017.08, The dipole orientation of guest emitters doped into host matrices is usually investigated by angular dependent photoluminescence (PL) measurements, which acquire an out-of-plane PL radiation pattern of the guest-host thin films. The PL radiation patterns generated by these methods are typically analysed by optical simulations, which require expertise to perform and interpret in the simulation. In this paper, we developed a method to calculate an orientational order parameter S without the use of full optical simulations. The PL radiation pattern showed a peak intensity (I sp) in the emission direction tilted by 40°-60° from the normal of the thin film surface plane, indicating an inherent dipole orientation of the emitter. Thus, we directly correlated I sp with S. The S - I sp relation was found to depend on the film thickness (d) and refractive indices of the substrate (n sub) and the organic thin film (n org). Hence, S can be simply calculated with information of I sp, d, n sub, and n org. We applied our method to thermally activated delayed fluorescence materials, which are known to be highly efficient electroluminescence emitters. We evaluated S and found that the error of this method, compared with an optical simulation, was less than 0.05.. |
| 89. | Takeshi Komino, Hiroyuki Kuwae, Akiko Okada, Weixin Fu, Jun Mizuno, Jean Charles Ribierre, Yuji Oki, Chihaya Adachi, In-Plane Anisotropic Molecular Orientation of Pentafluorene and Its Application to Linearly Polarized Electroluminescence, ACS applied materials & interfaces, 10.1021/acsami.7b05570, 9, 32, 27054-27061, 2017.08, By preparing parallelly aligned 1.9-μm-high SiO2 microfluidic channels on an indium tin oxide substrate surface, the solution flow direction during spin-coating was controlled to be parallel to the grating. Using this technique, a pentafluorene-4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) binary solution in chloroform was spin-coated to embed a 40-50 nm-thick 10 wt %-pentafluorene:CBP thin film in the channels. In-plane polarized photoluminescence measurements revealed that the pentafluorene molecules tended to orient along the grating, demonstrating that one-dimensional fluid flow can control the in-plane molecular orientation. Furthermore, the dependences of the photoluminescence anisotropy on the spin speed and substrate material suggest that the velocity of the solution flow and/or its gradient in the vertical direction greatly affects the resulting orientation. This indicates that the mechanism behind the molecular orientation is related to stress such as the shear force. The effect of the solution flow on the molecular orientation was demonstrated even in organic light-emitting diodes (OLEDs). Linearly polarized electroluminescence was obtained by applying the in-plane orientation to OLEDs, and it was found that the dichroic ratio of the electroluminescence orthogonal (x) and parallel (y) to the grating is x/y = 0.75.. |
| 90. | Takeshi Komino, Yuji Oki, Chihaya Adachi, Dipole orientation analysis without optical simulation: application to thermally activated delayed fluorescence emitters doped in host matrix, SCIENTIFIC REPORTS, 10.1038/s41598-017-08708-1, 7, 2017.08, The dipole orientation of guest emitters doped into host matrices is usually investigated by angular dependent photoluminescence (PL) measurements, which acquire an out-of-plane PL radiation pattern of the guest-host thin films. The PL radiation patterns generated by these methods are typically analysed by optical simulations, which require expertise to perform and interpret in the simulation. In this paper, we developed a method to calculate an orientational order parameter S without the use of full optical simulations. The PL radiation pattern showed a peak intensity (I-sp) in the emission direction tilted by 40 degrees-60 degrees from the normal of the thin film surface plane, indicating an inherent dipole orientation of the emitter. Thus, we directly correlated I-sp with S. The S - I-sp relation was found to depend on the film thickness (d) and refractive indices of the substrate (n(sub)) and the organic thin film (n(org)). Hence, S can be simply calculated with information of I-sp, d, n(sub), and n(org). We applied our method to thermally activated delayed fluorescence materials, which are known to be highly efficient electroluminescence emitters. We evaluated S and found that the error of this method, compared with an optical simulation, was less than 0.05.. |
| 91. | Takeshi Komino, Hiroyuki Kuwae, Akiko Okada, Weixin Fu, Jun Mizuno, Jean-Charles Ribierre, Yuji Oki, Chihaya Adachi, In-Plane Anisotropic Molecular Orientation of Pentafluorene and Its Application to Linearly Polarized Electroluminescence, ACS APPLIED MATERIALS & INTERFACES, 10.1021/acsami.7b05570, 9, 32, 27054-27061, 2017.08, By preparing parallelly aligned 1.9-mu m-high SiO2 microfluidic channels on an indium tin oxide substrate surface, the solution flow direction during spin-coating was controlled to be parallel to the grating. Using this technique, a pentafluorene-4,4'-bis(N-carbazoly1)-1,11-biphenyl (CBP) binary solution in chloroform was spin-coated to embed a 40-50 nm-thick 10 wt %-pentafluorene:CBP thin film in the channels. In-plane polarized photoluminescence measurements revealed that the pentafluorene molecules tended to orient along the grating, demonstrating that one-dimensional fluid flow can control the in-plane molecular orientation. Furthermore, the dependences of the photoluminescence anisotropy on the spin speed and substrate material suggest that the velocity of the solution flow and/or its gradient in the vertical direction greatly affects the resulting orientation. This indicates that the mechanism behind the molecular orientation is related to stress such as the shear force. The effect of the solution flow on the molecular orientation was demonstrated even in organic light-emitting diodes (OLEDs). Linearly polarized electroluminescence was obtained by applying the in-plane orientation to OLEDs, and it was found that the dichroic ratio of the electroluminescence orthogonal (x) and parallel (y) to the grating is x/y = 0.75.. |
| 92. | Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, L. Jay Guo, Xudong Fan, On-chip, high-sensitivity temperature sensors based on dye-doped solid-state polymer microring lasers, APPLIED PHYSICS LETTERS, 10.1063/1.4986825, 111, 6, 2017.08, We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/degrees C based on a rhodamine 6G (R6G)-doped SU-8 whispering gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 mu m height that provided detection sensitivity, and the chemically robust fused-silica microring resonator host platform guaranteed its versatility for investigating different functional polymer materials with different refractive indices. As a proof of concept, a dye-doped hyperbranched polymer (TZ-001) microring laser-based temperature sensor was simultaneously developed on the same host wafer and characterized using a free-space optics measurement setup. Compared to TZ-001, the SU-8 polymer microring laser had a lower lasing threshold and a better photostability. The R6G-doped SU-8 polymer microring laser demonstrated greater adaptability as a high-performance temperature-sensing element. In addition to the sensitivity, the temperature resolutions for the laser-based sensors were also estimated to be 0.13 degrees C and 0.35 degrees C, respectively. The rapid and simple implementation of micrometer-sized temperature sensors that operate in the range of 31 -43 degrees C enables their potential application in thermometry. Published by AIP Publishing.. |
| 93. | Hiroaki Nomada, Kinichi Morita, Hirokazu Higuchi, Hiroaki Yoshioka, Yuji Oki, Carbon–polydimethylsiloxane-based integratable optical technology for spectroscopic analysis, Talanta, 10.1016/j.talanta.2015.11.066, 166, 428-432, 2017.05, A polydimethylsiloxane (PDMS)-based optical system has been demonstrated. To suppress intense background radiation due to multiple internal scatting in a transparent material, a composite structure of a carbon–PDMS compound and PDMS was proposed. The index matching of the real part of the refractive index can suppress internal scattering, and an absorption of 99–99.7% was attained by using carbon micro particles and carbon nano tubes. The black-PDMS light channel functions as a light filter for straight pass, and an optical density of 5 was obtained by bending the filter.. |
| 94. | Hiroaki Yoshioka, Yuya Mikami, Soichiro Ryu, Shintaro Mitsui, Cong Chen, Naoya Nishimura, Yuji Oki, Silica-based inorganic microdisk cavity by the ink-jet printing method, CLEO: Applications and Technology, CLEO_AT 2017 , 10.1364/CLEO_AT.2017.JTu5A.119, Part F43-CLEO_AT 2017, 2017.05, We experimentally succeeded fabrication and WGM lasing of inorganic microdisks by the ink-jet printing method. This silica-based microdisk cavity is the first demonstration in ordinary pressure and temperature among inorganic microdisks.. |
| 95. | Hiroaki Nomada, Kinichi Morita, Hirokazu Higuchi, Hiroaki Yoshioka, Yuji Oki, Carbon-polydimethylsiloxane-based integratable optical technology for spectroscopic analysis, TALANTA, 10.1016/j.talanta.2015.11.066, 166, 428-432, 2017.05, A polydimethylsiloxane (PDMS)-based optical system has been demonstrated. To suppress intense background radiation due to multiple internal scatting in a transparent material, a composite structure of a carbon-PDMS compound and PDMS was proposed. The index matching of the real part of the refractive index can suppress internal scattering, and an absorption of 99-99.7% was attained by using carbon micro particles and carbon nano tubes. The black-PDMS light channel functions as a light filter for straight pass, and an optical density of 5 was obtained by bending the filter. (C) 2015 The Authors. Published by Elsevier B.V.. |
| 96. | Yuji Oki, Takashi Ohe, Hiroaki Yoshioka, Koji Kosaka, Takaaki Kanemaru, 6.3 eV duv generation based on microchip Nd YAG laser, Laser Ignition Conference, LIC 2017 Laser Ignition Conference, LIC 2017, 10.1364/LIC.2017.LWA5.10, Part F67-LIC 2017, 2017.01, Deep ultraviolet light source using passively Q-switch Nd:YAG laser was proposed and designed for soft laser ablation on scanning electron microscopic application. Design wavelength is from 193 nm to 196.7 nm that exceeds 6.3 eV in photon energy for chemical dissociation of organic sample. Frequency mixing of 4th harmonic beam and optical parametric generated red beam are adopted by using flux-less BBO crystal. Initial design of BBO and PPLN-OPG has been performed.. |
| 97. | Takeshi Komino, Yuta Sagara, Hiroyuki Tanaka, Yuji Oki, Nozomi Nakamura, Hiroshi Fujimoto, Chihaya Adachi, Highly efficient organic light-emitting diodes with completely oriented delayed fluorescent emitters, The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017 The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017, Part F82-CLEO_Europe 2017, 2017.01. |
| 98. | Cong Chen, Jifeng Li, Shintaro Mitsui, Soichiro Ryu, Yuya Mikami, Naoya Nishimura, Hiroaki Yoshioka, Yuji Oki, Investigation of protein adsorption for biosensors based on ink-jet printed active microdisk resonator, The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017 The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017, Part F82-CLEO_Europe 2017, 2017.01. |
| 99. | Harunobu Takeda, Cong Chen, Takeshi Komino, Hiroaki Yoshioka, Yuji Oki, Chihaya Adachi, THz absorption measurement and calculation of organic thermally activated delayed fluorescence materials, The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017 The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017, Part F82-CLEO_Europe 2017, 2017.01. |
| 100. | Yuya Mikami, Soichiro Ryu, Cong Chen, Naoya Nishimura, Hiroaki Yoshioka, Yuji Oki, Water-like-refractive-index microdisk cavity by the ink-jet printing method, The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017 The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017, Part F82-CLEO_Europe 2017, 2017.01. |
| 101. | Hiroaki Yoshioka, Yusuke Itoh, Ayumu Kiyomori, Yuji Oki, Controlling mobility speed of dye molecules in polydimethylsiloxane through molecular weight and solubility, OPTICAL MATERIALS EXPRESS, 10.1364/OME.6.003417, 6, 11, 3417-3426, 2016.11, We experimentally evaluated the control of the mobility speed of organic chromophores in polydimethylsiloxane (PDMS) by developing novel chromophores with different molecular structures. As novel chromophores, PDMS-soluble coumarin- and pyrromethene-based chromophores were developed by attaching heptamethyltrisiloxane (HMTS). Then, the optical and mobility properties of these novel chromophores were evaluated. The investigation of mobility characteristics revealed that molecular weight and solubility both influence the diffusion coefficient. In the case of low solubility, molecular weight is the dominant factor in determining the diffusion coefficient. On the other hand, molecular solubility is the dominant factor at high solubility. To the best of our knowledge, this is the first investigation on controlling the diffusion coefficient in PDMS through the molecular weight and solubility. (C) 2016 Optical Society of America. |
| 102. | Harunobu Takeda, Cong Chen, Takeshi Komino, Hiroaki Yoshioka, Yuji Oki, CHIHAYA ADACHI, 0.6 – 1.6 THz band spectroscopy of organic thermally activated delayed fluorescence materials, Optical Material Express, OME.6.003045, 6, 10, 3045-3052, 2016.10, [URL], Newly developed thermally activated delayed fluorescence (TADF) materials are attractive for application in efficient displays. Five TADF materials, including PXZ-TRZ and four carbazolyl dicyanobenzene (CDCB) derivatives of 4CzTPN, 4CzTPN – Ph, 2CzPN, and 4CzIPN, were investigated using terahertz spectroscopy in the 0.60 – 1.60 THz range. While PXZ-TRZ was almost transparent, the carbazolyl dicyanobenzene (CDCB) derivatives, especially 4CzIPN, exhibited intrinsic absorption features. Comparing these results with density functional theorem calculations, each absorption feature was clarified to originate from the intramolecular motions of the carbazole units.. |
| 103. | Hiroaki Yoshioka, Yusuke Itoh, Ayumu Kiyomori, Yuji Oki, Controlling mobility speed of dye molecules in polydimethylsiloxane through molecular weight and solubility, Optics Material Express, OME.6.003417, 6, 11, 3417-3426, 2016.10, [URL], We experimentally evaluated the control of the mobility speed of organic chromophores in polydimethylsiloxane (PDMS) by developing novel chromophores with different molecular structures. As novel chromophores, PDMS-soluble coumarin- and pyrromethene-based chromophores were developed by attaching heptamethyltrisiloxane (HMTS). Then, the optical and mobility properties of these novel chromophores were evaluated. The investigation of mobility characteristics revealed that molecular weight and solubility both influence the diffusion coefficient. In the case of low solubility, molecular weight is the dominant factor in determining the diffusion coefficient. On the other hand, molecular solubility is the dominant factor at high solubility. To the best of our knowledge, this is the first investigation on controlling the diffusion coefficient in PDMS through the molecular weight and solubility.. |
| 104. | Harunobu Takeda, Cong Chen, Takeshi Komino, Hiroaki Yoshioka, Yuji Oki, Chihaya Adachi, 0.6-1.6 THz band spectroscopy of organic thermally activated delayed fluorescence materials, OPTICAL MATERIALS EXPRESS, 10.1364/OME.6.003045, 6, 10, 3045-3052, 2016.10, Newly developed thermally activated delayed fluorescence (TADF) materials are attractive for application in efficient displays. Five TADF materials, including PXZ-TRZ and four carbazolyl dicyanobenzene (CDCB) derivatives of 4CzTPN, 4CzTPN - Ph, 2CzPN, and 4CzIPN, were investigated using terahertz spectroscopy in the 0.60-1.60 THz range. While PXZ-TRZ was almost transparent, the carbazolyl dicyanobenzene (CDCB) derivatives, especially 4CzIPN, exhibited intrinsic absorption features. Comparing these results with density functional theorem calculations, each absorption feature was clarified to originate from the intramolecular motions of the carbazole units. (C) 2016 Optical Society of America. |
| 105. | Takeshi Komino, Yuta Sagara, Hiroyuki Tanaka, Yuji Oki, Nozomi Nakamura, Hiroshi Fujimoto, Chihaya Adachi, Electroluminescence from completely horizontally oriented dye molecules, Applied Physics Letters, 10.1063/1.4954163, 108, 24, 2016.06, A complete horizontal molecular orientation of a linear-shaped thermally activated delayed fluorescent guest emitter 2,6-bis(4-(10Hphenoxazin-10-yl)phenyl)benzo[1,2-d:5,4-d′] bis(oxazole) (cis-BOX2) was obtained in a glassy host matrix by vapor deposition. The orientational order of cis-BOX2 depended on the combination of deposition temperature and the type of host matrix. Complete horizontal orientation was obtained when a thin film with cis-BOX2 doped in a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) host matrix was fabricated at 200 K. The ultimate orientation of guest molecules originates from not only the kinetic relaxation but also the kinetic stability of the deposited guest molecules on the film surface during film growth. Utilizing the ultimate orientation, a highly efficient organic light-emitting diode with the external quantum efficiency of 33.4 ± 2.0% was realized. The thermal stability of the horizontal orientation of cis-BOX2 was governed by the glass transition temperature (Tg) of the CBP host matrix; the horizontal orientation was stable unless the film was annealed above Tg.. |
| 106. | Takeshi Komino, Yuta Sagara, Hiroyuki Tanaka, Yuji Oki, Nozomi Nakamura, Hiroshi Fujimoto, Chihaya Adachi, Electroluminescence from completely horizontally oriented dye molecules, APPLIED PHYSICS LETTERS, 10.1063/1.4954163, 108, 24, 2016.06, A complete horizontal molecular orientation of a linear-shaped thermally activated delayed fluorescent guest emitter 2,6-bis(4-(10Hphenoxazin-10-yl)phenyl)benzo[1,2-d:5,4-d'] bis(oxazole) (cis-BOX2) was obtained in a glassy host matrix by vapor deposition. The orientational order of cis-BOX2 depended on the combination of deposition temperature and the type of host matrix. Complete horizontal orientation was obtained when a thin film with cis-BOX2 doped in a 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) host matrix was fabricated at 200 K. The ultimate orientation of guest molecules originates from not only the kinetic relaxation but also the kinetic stability of the deposited guest molecules on the film surface during film growth. Utilizing the ultimate orientation, a highly efficient organic light-emitting diode with the external quantum efficiency of 33.4+/-2.0% was realized. The thermal stability of the horizontal orientation of cis-BOX2 was governed by the glass transition temperature (T-g) of the CBP host matrix; the horizontal orientation was stable unless the film was annealed above T-g. Published by AIP Publishing.. |
| 107. | Hiroaki Nomada, Kin'ichi Morita, Hirokazu Higuchi, Hiroaki Yoshioka, Yuji Oki, Carbon–polydimethylsiloxane-based integratable optical technology for spectroscopic analysis, Talanta, 2015.12, A polydimethylsiloxane (PDMS)-based optical system has been demonstrated. To suppress intense background radiation due to multiple internal scatting in a transparent material, a composite structure of a carbon–PDMS compound and PDMS was proposed. The index matching of the real part of the refractive index can suppress internal scattering, and an absorption of 99%–99.7% was attained by using carbon micro particles and carbon nano tubes. The black-PDMS light channel functions as a light filter for straight pass, and an optical density of 5 was obtained by bending the filter.. |
| 108. | Hiroaki Yoshioka, Tomoya Ota, Cong Chen, Soichiro Ryu, Kei Yaui, Yuji Oki, Spectroscopic behavior in whispering-gallery modes by edge formation of printed microdisk lasers, Proceedings of SPIE, 2015.12. |
| 109. | Takaaki Kanemaru, Yuji Oki, Ultrathin sectioning with DUV-pulsed laser ablation: development of a laser ablation nano tome, MICROSCOPY, 10.1093/jmicro/dfv015, 64, 4, 289-296, 2015.08, The electrically automated ultrathin sectioning apparatus, which has been developed in recent years, can produce consecutive ultrathin sections with a diamond knife and a gallium ion beam. These newly developed apparatuses, however, have several shortcomings, such as the limited block cutting area, thermal damage to the sample by the focused ion beam and a sample electronic charge. To overcome these faults and for easier scanning electron microscopy three-dimensional fine structural reconstruction, we have developed a new cutting method using a deep ultraviolet laser, which we have named the 'LANTome (Light Ablation Nanotome)'. Using this method, we confirmed the widening of sectioning areas, shortening of the sectioning time, automatic smoothing of rough surfaces, no sample electronic charge and minimal heat effects on the sample tissue, such as thermal denaturation.. |
| 110. | Mitsuhiro Nakano, Noboru Hirakawa, Hiroaki Yoshioka, Yuji Oki, On-site three-dimensional fabrication of organic optical system with micro-dispensing method, Proceedings of 3nd EOS Conference on Optofluidics (EOSOF 2015), 2015.06. |
| 111. | Hiroaki Yoshioka, Tomoya Ota, Cong Chen, Soichiro Ryu, Kei Yaui, Yuji Oki, Extreme ultra-low lasing threshold of full-polymeric fundamental microdisk printed with room-temperature atmospheric ink-jet technique, SCIENTIFIC REPORTS, 10.1038/srep10623, 5, 2015.05, [URL], We experimentally demonstrated an extreme ultra-low lasing threshold from full-polymeric fundamental microdisk cavities fabricated by a novel fabrication method, the ink-jet printing method, which is much simpler and easier than previous methods such as lithography. The ink-jet printing method provides additive, room-temperature atmospheric, rapid fabrication with only two steps: (i) stacking cladding pedestal and waveguiding disk spots using the ink-jet technique, and (ii) partial etching of the cladding pedestal envelope. Two kinds of low-viscosity polymers successfully formed microdisks with high surface homogeneity, and one of the polymers doped with LDS798 dye yielded whispering-gallery-mode lasing. The fundamental disks exhibited an extremely ultra-low lasing threshold of 0.33 μJ/mm2 at a wavelength of 817.3 nm. To the best of our knowledge, this lasing threshold is the lowest threshold obtained among both organic and inorganic fundamental microdisk cavity lasers with a highly confined structure.. |
| 112. | Hiroaki Yoshioka, Noboru Hirakawa, Mitsuhiro Nakano, Yuji Oki, On-Demand Fabrication of Micro-Wired Rods and Nano-Coupling Control for 3D Polymeric Optical System, Technical Digest of CLEO 2015, 2015.05. |
| 113. | Hiroaki Yoshioka, Yuya Mikami, Soichiro Ryu, Shintaro Mitsui, Cong Chen, Naoya Nishimura, Yuji Oki, Silica-based Inorganic Microdisk Cavity by the Ink-jet Printing Method, Technical Digest of CLEO 2017, 2015.05. |
| 114. | Hiroaki Yoshioka, Tomoya Ota, Cong Chen, Soichiro Ryu, Kei Yasui, Yuji Oki, Extreme ultra-low lasing threshold of full-polymeric fundamental microdisk printed with room-temperature atmospheric ink-jet technique, SCIENTIFIC REPORTS, 10.1038/srep10623, 5, 2015.05, We experimentally demonstrated an extreme ultra-low lasing threshold from full-polymeric fundamental microdisk cavities fabricated by a novel fabrication method, the ink-jet printing method, which is much simpler and easier than previous methods such as lithography. The ink-jet printing method provides additive, room-temperature atmospheric, rapid fabrication with only two steps: (i) stacking cladding pedestal and waveguiding disk spots using the ink-jet technique, and (ii) partial etching of the cladding pedestal envelope. Two kinds of low-viscosity polymers successfully formed microdisks with high surface homogeneity, and one of the polymers doped with LDS798 dye yielded whispering-gallery-mode lasing. The fundamental disks exhibited an extremely ultra-low lasing threshold of 0.33 mu J/mm(2) at a wavelength of 817.3 nm. To the best of our knowledge, this lasing threshold is the lowest threshold obtained among both organic and inorganic fundamental microdisk cavity lasers with a highly confined structure.. |
| 115. | Takaoaki Kanemaru, Yuji Oki, Ultrathin sectioning with DUV-pulsed laser ablation: development of a laser ablation nano tome, Microscopy, 10.1093/jmicro/dfv015, 1-4, 2015.04, The electrically automated ultrathin sectioning apparatus, which has been developed in recent years, can produce consecutive ultrathin sections with a diamond knife and a gallium ion beam. These newly developed apparatuses, however, have several shortcomings, such as the limited block cutting area, thermal damage to the sample by the focused ion beam and a sample electronic charge. To overcome these faults and for easier scanning electron microscopy three-dimensional fine structural reconstruction, we have developed a new cutting method using a deep ultraviolet laser, which we have named the ‘LANTome (Light Ablation Nanotome)’. Using this method, we confirmed the widening of sectioning areas, shortening of the sectioning time, automatic smoothing of rough surfaces, no sample electronic charge and minimal heat effects on the sample tissue, such as thermal denaturation.. |
| 116. | Yuji Oki, On-site Micro Painting of Optical Laser Cavities for Microchip Laser Driving, OSA Technical Digest, 10.1364/LIC.2015.T4A.5, T4A.5, 2015.04, Two types of polymeric microcavity fabrication method for DPSS pumping lasers were proposed and developed. WGM lasers were successfully fabricated. Polymeric microdisk with LDS798-doped microdisk and Rhodamine-6G-doped micro-wire array were demonstrated.. |
| 117. | Hiroshi Yoneme, Junko Hatakeyama, Atsushi Danjo, Hanako Oida, Masao Yoshinari, Reona Aijima, Naohisa Murata, Toshiyuki Watanabe, Yuji Oki, Mizuho A. Kido, Milk basic protein supplementation enhances fracture healing in mice, Nutrition, 10.1016/j.nut.2014.08.008, 31, 2, 399-405, 2015.02, Objectives: There is an unmet need for agents that can stimulate bone healing. The goal of this study was to evaluate the effects of basic proteins from milk whey (milk basic protein [MBP]) on fracture healing in mice. Methods: Closed tibial transverse fractures were generated in 6-wk-old male C3 H/HeJ mice given either tap water or MBP-supplemented water for 3, 7, 14, 28, and 56d after fracture generation. The tibial tissues were analyzed by radiography, μCT, and a three-point bending test. The expression levels of genes associated with bone metabolism were analyzed by real-time reverse transcription-polymerase chain reaction. Results: Quantitative μCT analysis showed that MBP-treated fractured tibiae had a larger hard callus in the sectional area and a larger volume compared with fractured tibiae without MBP treatment. The expression levels of genes associated with chondrogenesis and osteogenesis showed greater increases in fractured tibiae with MBP treatment. Significant increases in the callus mechanical properties were found in MBP-treated tibiae. Conclusions: MBP supplementation has the potential to improve fracture healing and bone strength in mouse tibiae. MBP could be a potential safe, low-cost, and easily administered nutritional element to prevent secondary fractures in patients with bone fractures.. |
| 118. | Yuji Oki, Hiroaki Yoshioka, Cong Chen, Soichiro Ryu, Kei Yasui, Low-threshold lasing from organic and polymeric microdisk printed by room temperature atmosphere ink-jet technique , SPIE - the international society for optics and photonics, 10.1117/12.2078965, 9360, 936007, 2015.01. |
| 119. | Tokuma Nakamichi, Yu Yang, Tomoya Ohta, Hiroaki Yoshioka, Masayuki Yahiro, Masanao Era, Hirofumi Watanabe, Yuanjing Cui, Yuji Oki, Guodong Qian, Stackable spectral-sensitive conductive films based on cyanine aggregates via an inkjet method, DYES AND PIGMENTS, 10.1016/j.dyepig.2013.03.013, 98, 3, 333-338, 2013.09, In this work, wavelength sensitive organic bulk-hetero photodiodes were fabricated by a piezoelectric inkjet method based on the J-type aggregates of cyanine dye molecules doped into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) thin films on indium tin oxide anodes. The cyanine dye concentration in the inkjet printed films was optimized and the J-aggregate formation during the drying process was investigated by local absorption spectra. It was found that at lower dye concentrations, not only the J-aggregate formation but also the radiation sensitivities of the films were improved significantly. Moreover, the stacking of the,cyanine dye - poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) spots demonstrated the linear increase on the optical density and filth thickness without deteriorating the J-aggregate formation, indicating their potential in application as narrow band filters. (c) 2013 Elsevier Ltd. All rights reserved.. |
| 120. | Noboru Hirakawa, Horoyuki Kubota, Hiroaki Yoshioka, Noriyasu Tarumi, Yoshio Kagebayashi, Yuji Oki, Micro-dispensing for three-dimensional direct fabrication of laser waveguides, Optical Society of America, paper WS3_3., 2013.07, [URL]. |
| 121. | Kota Kuwamitsu, Hiroaki Yoshioka, Nahoko Naruishi, Yoshihide Tanaka, Yuji Oki, Print-like Fabrication of Laser Systems in PDMS Flowchip, 2nd EOS Conference on Optofluidics 2013, 2, 1569714773_004_1-1569714773_004_2, 2013.05, Fully print-like fabrication for polymeric and optically pumped laser system in PDMS chip was demonstrated. The pumping planer waveguides and dye doped line waveguide were combined for integratable laser and pumping optical system via fiber pumping. Flow channel coupling was also studied.. |
| 122. | Tomoya Oya, Hiroaki Yoshioka, Kei Yasui, Daisuke Maeda, Yuji Oki, Printed Fabrication of Microdisk at Room Temperature, 2nd EOS Conference on Optofluidics 2013, 2, 1569714735_1-1569714735_2, 2013.05, Novel fabrication process for polymeric microdisk was proposed and demonstrated by ink-jet technique for the first time. Extremely low viscosity of hyper-branched polymers and solubility control based on Hansen parameters were combined. They can stack thick polymeric disks and only three shots of droplet can fabricate microdisks.. |
| 123. | Hiroaki Yoshioka, Yusuke Itoh, Ayumu Kiyomori, Yuji Oki, Degradation self-recovery and durability extension on solid-state dye laser in blue region, Optical Society of America, 10.1364/CLEO_SI.2013.CF1I.5, 2013.05, [URL], We developed a degradation-recoverable PDMS dye laser using a new fluorene-based chromophore. The chromophore has dimethylsiloxane chains to enhance its solubility in the PDMS matrix. It extended the durability by a factor of 20.. |
| 124. | Hiroaki Yoshioka, Yuji Oki, Nd:YAG/Cr:GSGG passively Q-switched compact DPSS laser with flexure-frame structure, Proceedings of The 1st. Laser Ignition Conference '13, LIC4-3-1-LIC4-3-2, 2013.04. |
| 125. | Hiroaki Yoshioka, Yusuke Itoh, Ayumu Kiyomori, Masanao Era, Yuji Oki, Fluorene-based chromophore for degradation-recoverable solid-state dye laser, OPTICAL MATERIALS EXPRESS, 10.1364/OME.3.000176, 3, 2, 176-183, 2013.02, We developed a new fluorene-based chromophore for a degradation-recoverable polydimethylsiloxane (PDMS) dye laser. The chromophore has dimethylsiloxane chains to enhance its solubility in the PDMS matrix. The spectroscopic and mobile characteristics were evaluated, and the attaching of the siloxane/silyl chains improved solubility in PDMS without influencing the laser property. It extended the durability by a factor of 20 for shots in an index-type Bragg grating/PDMS complex laser waveguide compared with a similar fluorene-based chromophore in PMMA laser waveguides. This molecular diffusion not only increased durability but also provided detailed information about dye degradation in waveguides. (C) 2013 Optical Society of America. |
| 126. | Yuji Oki, Hiroaki Yoshioka, Tokuma Nakamichi, Masayuki Yahiro, Masaya Miyazaki, Masanao Era, Hirofumi Watanabe, Spectral-resolving capable and integratable multilayered conductive films via an inkjet method, JOURNAL OF MATERIALS CHEMISTRY C, 10.1039/c2tc00743f, 1, 9, 1739-1744, 2013.01. |
| 127. | Development of Integratable Laser for Optofluidic Chip. |
| 128. | Yuji Oki, Printable laser system on a film and an optical fiber, International Conference on Fibre Optics and Photonics, 20(2011), p.4690-4696, 2012.12. |
| 129. | Medical Lasers on Wavelength Tables, and Their History Many kinds of lasers have been used in medical applications, and new laser technologies will also adopted for photo-diagnostics and photo-therapy. In these special review articles, we tried to introduce the new laser technologies. As an introductory review, traditional and standard line-up of medical lasers is reviewed from a point of users' view.. |
| 130. | Hiroyuki Kubota, Soichiro Oomi, Hiroaki Yoshioka, Hirofumi Watanabe, Yuji Oki, Optical bending sensor using distributed feedback solid state dye lasers on optical fiber, OPTICS EXPRESS, 10.1364/OE.20.014938, 20, 14, 14938-14944, 2012.07, Novel type of optical fiber sensor was proposed and demonstrated. The print-like fabrication technique fabricates multiple distributed feedback solid state dye lasers on a polymeric optical fiber (POF) with tapered coupling. This multi-active-sidecore structure was easily fabricated and provides multiple functions. Mounting the lasers on the same point of a multimode POF demonstrated a bending radius sensitivity of 20 m without any supports. Two axis directional sensing without cross talk was also confirmed. A more complicated mounting formation can demonstrate a twisted POF. The temperature property of the sensor was also studied, and elimination of the temperature influence was experimentally attained. (c) 2012 Optical Society of America. |
| 131. | Yuji Oki, Solid state dye laser system as surface integratable active waveguide, Collaborative Conference on Materials Research 2012, 20(2011), p.4690-4696, 2012.06. |
| 132. | Hiroaki Yoshioka, Yu Yang, Hirofumi Watanabe, and Yuji Oki, Fundamental characteristics of degradation- recoverable solid-state DFB polymer laser, Optics Express, 20, 4, 20(2011), p.4690-4696, 2012.02. |
| 133. | Hiroaki Yoshioka, Yu Yang, Hirofumi Watanabe, Yuji Oki, Fundamental characteristics of degradation-recoverable solid-state DFB polymer laser, OPTICS EXPRESS, 10.1364/OE.20.004690, 20, 4, 4690-4696, 2012.02, A novel solid-state dye laser with degradation recovery was proposed and demonstrated. Polydimethylsiloxane was used as a nanoporous solid matrix to enable the internal circulation of dye molecules in the solid state. An internal circulation model for the dye molecules was also proposed and verified numerically by assuming molecular mobility and using a proposed diffusion equation. The durability of the laser was increased 20.5-fold compared with that of a conventional polymethylmethacrylate laser. This novel laser solves the low-durability problem of dye-doped polymer lasers. (C) 2012 Optical Society of America. |
| 134. | Kota Kuwamitsu, Hiroaki Yoshioka, Hirofumi Watanabe, Nahoko Naruishi, Yoshihide Tanaka and Yuji Oki, Laser integrated PDMS optofluidic chip for flowcytometry using Cy5 dye detection, 第64回電気関係学会九州支部連合大会, 64, 64(2011), p., 2011.09. |
| 135. | Hirotaka So, Hirofumi Watanabe, Masayuki Yahiro, Yu Yang, Yuji Oki, and Chihaya Adachi, Highly efficient distributed-feedback waveguide blue laser using spirobifluorene derivative, IQEC/CLEO Pacific Rim 2011, 1007-1008, (2011), p., 2011.09. |
| 136. | Hiroyuki Kubota, Hiroaki Yoshioka, Hirofumi Watanabe, Yuji Oki, Novel laser switching system for organic waveguide laser array, 第64回電気関係学会九州支部連合大会, 64, 64(2011), p., 2011.09. |
| 137. | Kota Kuwamitsu, Hiroaki Yoshioka, Ryo Goto, Hirofumi Watanabe, Nahoko Naruishi, Yoshihide Tanaka and Yuji Oki, Integration of Distributed-feedback (DFB) Solid-state Dye Lasers with Optical Pumping Systems for PDMS Micro Biochemistry Chips, IQEC/CLEO Pacific Rim 2011, 378-380, (2011), p, 2011.08. |
| 138. | Hiroyuki Kubota, Soichiro Oomi, Hirofumi Watanabe, Yuji Oki, Bending and Twisting Sensor Using Multiple-Waveguide Solid-State Dye Lasers on a Plastic Optical Fiber, IQEC/CLEO Pacific Rim 2011, 676-678, (2011), p, 2011.08. |
| 139. | Tokuma Nakamichi, Yu Yang, Hiroaki Yoshioka, Soichieo Omi, Hirofumi Watanabe, and Yuji Oki , Printable DFB Laser and Wavelength Monitor Systems by On Demand Fabrication on Flexible Films, CLEO: Science and Innovations (CLEO: S and I) 2011 paper, (2011), CTuM7, 2011.05. |
| 140. | Tokuma Nakamichi, Yu Yang, Soichiro Omi, Hiroaki Yoshioka, Hirofumi Watanabe, Masayuki Yahiro, Masanao Era, Yuji Oki, Monochromatic Organic Photodiodes Made by Stackable Ink-jet Fabrication for Integrated Laser Chips, CLEO: Science and Innovations (CLEO: S and I) 2011 paper, (2011), CWF6, 2011.05. |
| 141. | Hiroaki Yoshioka, Ryo Goto, Soichiro Omi, Yu Yang, Yuji Oki, Solid-State Polymer Waveguide DFB Laser with Self Dye-Circulatory Function, CLEO: Applications and Technology (CLEO: A and T) 2011 paper, (2011), JTuI788, 2011.05. |
| 142. | Hiroaki Yoshioka, Wang Weibo, Kota Kuwamitsu, Wataru Iwasaki, Yukihiko Yamashita, Nobuo Miyadera, Yuji Oki, High Efficient Laser Action by Nd3+ Complex, CLEO: Science and Innovations (CLEO: S and I) 2011 paper, (2011), CMP5, 2011.05. |
| 143. | Soichieo Omi, Hiroyuki Kubota, Hiroaki Yoshioka, Hirofumi Watanabe, Yuji Oki, Direct Laser fabrication on Polymeric Optical Fiber and Its Sensor Application, CLEO: Science and Innovations (CLEO: S and I) 2011 paper: , (2011), CTuY5, 2011.05. |
| 144. | Hiroaki Yoshioka, Ryo Goto, Soichiro Omi, Yu Yang, Yuji Oki, Degradation Recoverable DFB Lasers Based on P597:PDMS/PTFEMA, The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2011 paper: , (2011), CE7_1, 2011.05. |
| 145. | Hirotaka So, Hirofumi Watanabe, Masayuki Yahiro, Yu Yang, Yuji Oki, Chihaya Adachi, Highly photostable distributed-feedback polymer waveguide blue laser using spirobifluorene derivatives, Optical Materials, 33, 6, 755-758 , 33(2011), p., 2011.04. |
| 146. | Hirotaka So, Hirofumi Watanabe, Masayuki Yahiro, Yu Yang, Yuji Oki, Chihaya Adachi, Highly photostable distributed-feedback polymer waveguide blue laser using spirobifluorene derivatives, OPTICAL MATERIALS, 10.1016/j.optmat.2010.12.011, 33, 6, 755-758, 2011.04, In this study, we synthesized the new spirobifluorene derivatives; hexylbiphenyl-spirobifluorene (HBP-Spiro) and triphenylamine-spirobifluorene (TPA-Spiro) and demonstrated the operation of a distributed-feedback polymer waveguide blue laser. In addition, we investigated the optical and lasing properties of spirobifluorene derivatives including photostability. The experimental slope efficiency and the energy threshold of a HBP-Spiro-doped waveguide laser were 3.6% and 1.9 mu J, respectively. An operation lifetime of 27,000 shots was obtained for a pump-pulse duration of 1.2 ns and energy of 3.0 mu J at a wavelength of 355 nm. (C) 2011 Elsevier B.V. All rights reserved.. |
| 147. | Yu Yang, Tokuma Nakamichi, Hiroaki Yoshioka, Soichiro Omi, Ryo Goto, Hirofumi Watanabe，Yuji Oki, Intensity Sensitive Organic Photodiodes Patterned by Inkjet Method, Molecular Crystals and Liquid Crystals , 538, 1, 136-142, 538(2011), p., 2011.03. |
| 148. | Hiroaki Yoshioka, Weibo Wang, Kota Kuwamitsu,Wataru Iwasaki Kukihiko Yamashita, Nobuo Miyadera, Yuji Oki, Laser Action of Nd-Complex-Doped Polymer Laser Based on Liquid, Molecular Crystals and Liquid Crystals , 539, 1, 225-230, 539(2011), p., 2011.03. |
| 149. | Yu Yang, Soichiro Omi, Ryo Goto, Masayuki Yahiro, Masanao Era, Hirofumi Watanabe, Yuji Oki, Wavelength sensitive photodiodes in the visible based on J-type aggregated films patterned by inkjet method, ORGANIC ELECTRONICS, 10.1016/j.orgel.2010.11.011, 12, 3, 405-410, 2011.03, In this study, a kind of disposable and miniaturized organic photodiodes in the visible has been developed based on the J-type aggregated cyanine dyes films by the drop-on-demand inkjet method. Wavelength sensitivity has been found by measuring the open-circuit voltage (Voc) of the organic photodiodes under the excitation of laser pulses at various wavelengths and high spectral resolution around the absorption peak of each cyanine dye J-aggregates can be obtained, where a sharp decrease on the Voc and a Voc in reverse direction are observed. The mechanism responsible for the sharp decrease and reverse Voc are discussed and the feasibility of using the laser output from a solid-state dye laser waveguide as the excitation source for the organic photodiodes which may be possibly integrated together onto the flow-cytometry chips in the future are also demonstrated. (C) 2010 Elsevier B. V. All rights reserved.. |
| 150. | Soichiro OMI, Hiroyuki KUBOTA, Yu YANG, Hirofumi WATANABE, Yuji OKI, Tunable Waveguide Dye Laser on a Plastic Optical Fiber , IEEE Xplore /TENCON2010, 444-445, 2011.01. |
| 151. | Hirotaka So, Hirofumi Watanabe, Yu Yang, Yuji Oki, Masayuki Yahiro, Chihaya Adachi, A distributed-feedback organic waveguide blue laser using spirobifluorene derivatives, IEEE Xplore /TENCON2010, 440-443, 2011.01. |
| 152. | Tokuma Nakamichi, Yu Yang, Soichiro Omi, Ryo Goto, Hirofumi Watanabe, Yuji Oki Masayuki Yahiro, Masanao Era, Spectroscopic Properties of J-aggregated Cyanine in Micro-sized Film by Ink-jet Spotting, IEEE Xplore /TENCON2010, 129-133, 2011.01. |
| 153. | Hiroyuki Kubota, Soichiro Oomi, Hiroaki Yoshioka, Hirofumi Watanabe, and Yuji Oki, Optical bending sensor using distributed feedback solid state dye lasers on optical fiber, Optics Express, 20, 4, 20(2011), p.4690-4696, 2011.01. |
| 154. | Yu Yang, Soichiro Omi, Ryo Goto, Masayuki Yahiro, Masanao Era, Hirofumi Watanabe, Yuji Oki, Wavelength Sensitive Photodiodes in the Visible based on J-type Aggregated Films Patterned by Inkjet Method, Organic Electronics, 12, 3, 405-410, 2010.11. |
| 155. | Yu Yang, Ryo Goto, Soichiro Omi, Kenchi Yamashita, Hirofumi Watanabe, Masaya Miyazaki, and Yuji Oki, Highly photo-stable dye doped solid-state distributed-feedback (DFB) channeled waveguide lasers by a pen-drawing technique, Optics Express, 18, 21, 22080-22089, 2010.10. |
| 156. | Yu Yang, Ryo Goto, Soichiro Omi, Kenchi Yamashita, Hirofumi Watanabe, Masaya Miyazaki, Yuji Oki, Highly photo-stable dye doped solid-state distributed-feedback (DFB) channeled waveguide lasers by a pen-drawing technique, OPTICS EXPRESS, 10.1364/OE.18.022080, 18, 21, 22080-22089, 2010.10, Pyrromethene dyes doped polymeric channeled waveguide lasers with permanent DFB structures were fabricated via a novel pen-drawing technique with the patterned polydimethylsiloxane (PDMS) chips fabricated through a casting process as the substrates. With the high resolution dispensers, dye doped high viscosity pre-polymers were written into the PDMS grooves and the cross-section of the channeled waveguides could be controlled by both the polymer composition and the pen-drawing parameters. Highly stable laser output with 4.8 x 10(6) pulses of laser lifetime at 500 Hz of pump repetition rate has been obtained, which is suggested to be among one of the best results of pyrromethene 567 (PM567) up to date. (C) 2010 Optical Society of America. |
| 157. | Hiroaki Yoshioka1, Wang Weibo1, Kota Kuwamitsu1, Wataru Iwasaki2, Yukihiko Yamashita2, Nobuo Miyadera2 and Yuji Oki, Laser action of Nd-Complex-Doped Polymer Laser Based on Liquid, KJF2010, PB097, 2010.09. |
| 158. | Yu Yang, Tokuma Nakamichi, Hiroaki Yoshioka, Soichiro Omi, Ryo Goto, Hirofumi Watanabe, and Yuji Oki , Intensity Sensitive Organic Photodiodes Patterned by Inkjet Method, KJF2010, PA034, 2010.09. |
| 159. | Tokuma Nakamichi, Yu Yang, Soichiro Omi, Hirofumi Watanabe, Masayuki Yahiro, Masanao Era, Yuji Oki, Improvement of quantum efficiency (QE) of wavelength sensitive organic photo-diode by introduction of electron and hole transport layer, 第63回電気関係学会九州支部連合大会, 63, 659, 2010.09. |
| 160. | Hirofumi Watanabe, Hirotaka So, Yuji Oki, Shigehisa Akine, Takashige Omatsu, Picosecond-Pulse-Pumped Distributed-Feedback Thick-Film Waveguide Blue Laser Using Fluorescent Brightener 135, Jpn. J. Appl. Phys., 49, 72105, 2010.06. |
| 161. | Yu Yang, Hajime Imaoka, Kenchi Yamashita, Noriyuki Kamogawa, Hirofumi Watanabe, Masaya Miyazaki, Yuji Oki, Patterning on Cyanine-Dye-Doped Conductive Polymer Films by Ink Jet Method, Jpn. J. Appl. Phys., 49, 10204, 2010.01. |
| 162. | Soichiro Omi, Noriyuki Kamogawa, Yu Yang, Hirofumi Watanabe, Yuji Oki, Development print-like fabrication techniques for distributed feedback solid state dye lasers with multiple-layered structure, Proc. of SPIE, 7599, 75990T, 2010.01. |
| 163. | Yu Yang, Tokuma Nakamichi, Soichiro Omi, Ryo Goto, Masayuki Yahiro, Masano Era, Hirofumi Watanabe, Yuji Oki, Wavelength resolution improvement on organic photodiodes made by ink-jet technique, Proc. of SPIE, 7599, 75991D, 2010.01. |
| 164. | Hirofumi Watanabe, Yuji Oki, Takashige Omatsu, Highly Efficient Long-Lifetime Dual-Layered Waveguide Dye Laser Containing SiO2 Nanoparticle-Dispersed Random Scattering Active Media, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.1143/JJAP.48.112503, 48, 11, 2009.11, We have demonstrated a highly efficient, long-lifetime waveguide dye laser using nanosized-particle-dispersed random scattering active media An experimental laser slope efficiency of 38.6% and energy threshold of less than 1 mu J at a single longitudinal mode were measured The operation lifetime of this laser device reached 6.5 million pump shots (C) 2009 The Japan Society of Applied Physics. |
| 165. | アクリル・シリコーンフィルムに両対応したディスポーザブル可変波長フィルムレーザー. |
| 166. | Primitive Integration of Waveguide DFB Dye lasers and Electrophoresis Chip. |
| 167. | 導波型DFB色素レーザーと電気泳動スライドチップの試験的融合. |
| 168. | Yu Yang, Shusaku KATAOKA, Noriyuki KAMOGAWA, Hirofumi WATANABE, Kenichi Yamashita, Masaya Miyazaki, Yuji OKI, Incorporable DFB Dye Lasers for Micro-flow-channels on a Polymeric Chip, CLEO/QELS, CThZ6, 2008.05. |
| 169. | Yuji Oki, Takahiro Okaguchi, HirofumiWatanabe and Tatsuo Okada, Development of Dual-Phase-Modulators Integrated QPM-SHG Waveguide?equilateral/inequilateral-scheme?, CLEO/QELS, CFK3, 2008.05. |
| 170. | Yuji OKI, Shusaku KATAOKA, Noriyuki KAMOGAWA, Hirofumi WATANABE, Kenichi Yamashita, Masaya Miyazaki, Integration of Multiple-DFB Dye Lasers and Microflow-Channel on a Polymeric Chip, Proceedings Advanced Solid State Photonics 2008, 2008.01. |
| 171. | Noriyuki KAMOGAWA, Shusaku KATAOKA, Koichi SANADA, Masamitsu TANAKA, Hirofumi WATANABE, Yiji Oki, Development Thermo-Optical Quasi-Mode-Coupling DFB Dye Laser with Pen-Drawing Fabrication, The 6th Asia Pacific Laser Symposium, pp.54, 2008.01. |
| 172. | Shusaku KATAOKA, Noriyuki KAMOGAWA, Masamitsu TANAKA, Hirofumi WATANABE, Kenichi YAMASHITA, Masaya MIYAZAKI, Satoru KUHARA, Yuji OKI, Polymeric microflowcytometry chip integrated with Mulitple-colored filme DFB Lasers, Technical Digest of The 6th Asia Pacific Laser Symposium, pp.53, 2008.01. |
| 173. | Hajime Imaoka, Hirofumi Watanabe, Yuji Oki, Development of Laser-Induced Breakdown Spectroscopy System with Palm-top Nd:YAG Laser, The 6th Asia Pacific Laser Symposium, pp.53, 2008.01. |
| 174. | S. Kataoka, H. Watanabe, Y. Oki, K. Yamashita, M. Miyazaki, Direct Coupling of Multi-color Film Dye Lasers to a Micro-flow-channel on a Polymeric Chip, International Session in Joint Conference of Electric and Electronics Engineering in Kyushu, pp.137,, 2007.09. |
| 175. | H. Imaoaka, H. Watanabe, Y. Oki, Development of Palm-Top 1064nm Laser System for Detection by Laser-Induced Breakdown Spectroscopy, International Session in Joint Conference of Electric and Electronics Engineering in Kyushu, pp.138, 2007.09. |
| 176. | N. Kamogawa, S. Kataoka, K. Sanada, M. Tanaka, H. Watanabe, Y. Oki, Development Thermo-Optical Quasi-Mode-Coupling DFB Dye Laser with Pen-Drawing Fabrication, International Session in Joint Conference of Electric and Electronics Engineering in Kyushu, pp.140, 2007.09. |
| 177. | S. Kataoka, H. Watanabe, Y. Oki, K. Yamashita, M. Miyazaki, Direct Coupling of Multi-color Film Dye Lasers to a Micro-flow-channel on a Polymeric Chip, The 7th Pacific Rim Conference on Lasers and Electro-Optics, pp.MF1-4, 2007.08. |
| 178. | N. Kamogawa, H. Watanabe, Y. Oki, K. Kitamura, S. Takekawa, Y. Urata, S. Wada, Development of Compact 473nm Laser Using Intra-Cavity SHG with Short-PPSLT, The 7th pacific Rim Conference on Lasers and Electro-Optics, pp.ThP-013, 2007.08. |
| 179. | H. Watanabe, Y. Oki, T. Omatsu, Highly efficient pico-second waveguide dye laser based on a random active medium, CLEO/Europe 2007, pp.CJ-12-TUE, 2007.06. |
| 180. | Y. Oki, T. Okaguchi, H. Watanabe, T. Okada, Modulatable and monolithic SHG waveguide based on PPLN and EO-phase-modulator, CLEO/Europe 2007, pp.CD8-6-THU, 2007.06. |
| 181. | Masamitsu Tanaka, Yuji Oki, Daisuke Nagano, Byeong-Kwan An, Soo Young Park, Distributed Feedback Waveguide Laser of Organic Nano-compound Material, Mol. Cryst. Liq. Cryst., volume=463, pages="455--465", 2007.04. |
| 182. | Yuji Oki, Yukinori Ogawa, Kenichi Yamashita, Masaya Miyazaki, Mitsuo Maeda, Integration of Optical Pumped Dye Laser on Organic Microflowcytometry Chip , Mol. Cryst. Liq. Cryst., volume=463, pages="413--422", 2007.04. |
| 183. | Masamitsu Tanaka, Yuji Oki, Daisuke Nagano, Byeong-Kwan An, Soo Young Park, Mitsuo Maeda, Distributed feedback waveguide laser of organic nano-compound material, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 10.1080/15421400601027908, 463, 455-465, 2007.02, The laser action was firstly demonstrated using 1-cyano-trans-1,2-bis-(4'-methyl-biphenyl)ethylene (CN-MBE), that enhances its fluorescence from organic nanoparticle. The CN-MBE is not fluorescent and has enhanced fluorescence in aggregated nanoparticle state. CN-MBE doped PMMA film showed fluorescence over 400 similar to 600nm and spectral narrowed emission at 430nm under pumping with a nanosecond pulsed laser at wavelength of 355 nm. CN-MBE: PMMA DFB laser waveguides were successfully fabricated, and lasing wavelength was over 430 to 490 nm. CN-MBE: PMMA DFB lasers showed laser threshold of 73 mu J/cm(2) at the waveguide size of 15 mu m x 100 mu m x 5 mu m. The output spectra had bandwidth as narrow as 60pm FWHM, and suppressed fluorescence background of less than 0.5%. The maximum peak power and average power were estimated to be 5W and 0.35 mu W, respectively. The durability was as long as 1.7 x 10(4) shots/waveguide.. |
| 184. | Yuji Oki, Yukinori Ogawa, Kenichi Yamashita, Masaya Miyazaki, Mitsuo Maeda, Integration of optical pumped dye laser on organic microflowcytometry chip, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 10.1080/15421400601027684, 463, 413-422, 2007.02, Integration techniques of tunable film dye laser on a plastic optical application chip were studied. The developed film dye lasers were waveguided distributed feedback (DFB) lasers, and they can cover the wavelength from 400 to 1100 nm. We fabricated microflowcytometry chip integrated with DFB film lasers as a first example. Partly film-coating technique and film lithography fabrication with an excimer laser were tried and combined each other. The film DFB dye laser was found as an useful technique for multi-color laser integration, and they showed comparable performance our traditional spin-coated film dye lasers.. |
| 185. | Takahiro Okaguchi, Hiromitsu Onda, Yuji Oki, Tatsuo Okada, Designing and Development of QPM-SHG PPLN Waveguide with Integrated Dual EO Modulator, Technical Digest of 5th International Conference on Optics-photonics Design & Fabrecation (ODF'06), Page 7PS2-20, 2006.12. |
| 186. | Koichi Sanada, Masamitsu Tanaka, Hirofumi Watanabe, Yuji Oki, Thermo-Optical Control on Quasi-Mode-Coupling DFB Laser, Technical Digest of 5th International Conference on Optics-photonics Design & Fabrecation (ODF'06), Page 7PS2-23, 2006.12. |
| 187. | Daisuke Nakamuta, Yuji Oki, Takashi Higotani, Takayuki Takao, Mitsuo Maeda, Nanometer-Scale Depth Resolution, Sensitive Surface Analysis Using Laser Ablation Atomic Fluorescence Spectroscopy, JJAP, Volume45, Number6A, Pages 5322-5325, 2006.06. |
| 188. | Yuji Oki, Hiromitsu Onda, Takahiro Okaguchi, Kenta Ohnishi, Tatsuo Okada, Development of quasi-phase-matched, second-harmonic generation periodically poled lithium niobate waveguide with an integrated electro-optical modulator, Optics Letters, Volume 31, Number 10, pages 1492-1494, 2006.05. |
| 189. | Yuji Oki, Yukinori Ogawa, Hirofumi Watanabe, Mitsuo Maeda, Coupling Control on Quasi-End-Fired DFB Film Dye Laser on a Plastic Chip, Technical digest of CLEO/QELS 2006, pages CFJ2, 2006.05. |
| 190. | Hirofumi Watanabe, Yuji Oki, Mitsuo Maeda, Takashige Omatsu, High-Peak Power Output from a Waveguide Dye Laser Based on a Random Active Layer, Technical digest of CLEO/QELS 2006, pages JWB51, 2006.05. |
| 191. | Y Oki, H Onda, T Okaguchi, K Ohnishi, T Okada, Development of a quasi-phase-matched, second-harmonic generation periodically poled lithium niobate waveguide with an integrated electro-optical modulator, OPTICS LETTERS, 10.1364/OL.31.001492, 31, 10, 1492-1494, 2006.05, A novel type of waveguide quasi-phase-matched device with output electro-optical (EO) modulation is proposed and demonstrated. The second-harmonic generated output can be modulated with a high extinction ratio by integration of dual EO phase modulators on a periodically poled lithium niobate waveguide. Blue and green coherent light with EO modulation was demonstrated, and wavelength dispersion of r(33) is discussed. (c) 2006 Optical Society of America.. |
| 192. | Yuji Oki, Masamitsu Tanaka, Yukinori Ogawa, Hirofumi Watanabe, Mitsuo Maeda, Development of Quasi-End-Fired Waveguide Plastic Dye Laser, J. of IEEE, Volume QE-42, Number 4, pages 389-396, 2006.04. |
| 193. | Yuji Oki, Masamitsu Tanaka, Yukinori Ogawa, Hirofumi Watanabe, Mitsuo Maeda, Development of quasi-end-fired waveguide plastic dye laser, IEEE Journal of Quantum Electronics, 10.1109/JQE.2006.871557, 42, 4, 389-396, 2006.04, A quasi-end-fire (QEF) pumping scheme was proposed and studied as a novel laser-pumping-scheme for a laser-dye-doped plastic waveguide laser with distributed feedback. This pumping scheme resembled longitudinal pumping, but also has the advantage of controllable absorption length of the injected pump beam. A first demonstration of the QEF was performed and the pumping beam controlling was also investigated. © 2006 IEEE.. |
| 194. | Trial on integration of conversion-efficiency-modulation on periodically-poled SHG device. |
| 195. | Numerical Analysis of Scattering Atoms for Laser Ablation Atomic Fluorescence Spectroscopy Extremely trace element analysis of solid surface using UV laser ablation technique has been developed and a simple numerical simulation of scattering atoms by laser ablation was performed. Calculation model shows a very good agreement with experimental results in a vacuum condition by using Maxwellian velocity distribution and forward peaked angular distribution. The atomic distribution in buffer gas was also investigated. Experiment with two dimensional imaging LIF spectroscopy and caluculation using Monte Carlo simulation method were performed.. |
| 196. | Daisuke Nakamura, Takayuki Takao, Yuji Oki, Mitsuo Maeda, Active Control of the ablation plume for laser ablation atomic fluorescence spectroscopy, Proc. of SPIE, Volume 6106, pages 61061A-1-10, 2006.01. |
| 197. | Yuji Oki, Yukinori Ogawa, Kennichi Yamashita, Hirofumu Watanabe, Masaya Miyazaki, Mitsuo Maeda, Integration of plastic waveguide lasers on film, its application, Proc. of SPIE, Volume 6123, pages 612313-1-11, 2006.01. |
| 198. | Yuji Oki, Shotaro Miyawaki, and Mitsuo Maeda, Spectroscopic Applications of Integrated Tunable Solid-State Dye Laser, Opt. Review., 10.1007/s10043-005-0301-x, 12, 4, 301-306, Volume 12, pages 301-305, 2005.08. |
| 199. | Y Oki, S Miyawaki, M Maeda, M Tanaka, Spectroscopic applications of integrated tunable solid-state dye laser, OPTICAL REVIEW, 12, 4, 301-306, 2005.07, A novel type of tunable laser is developed that integrates dye-doped plastics laser waveguides with a distributed feedback structure. The waveguide matrix is dye doped poly-hydroxyethylmethacrylate:methylmethacrylate, and a single-mode waveguide is achieved by refractive index control. The wavelength coverage is over 560-1100 nm using a frequency doubled Nd:YAG microchip laser. The miniaturizing of the optical-pumped solid-state dye laser extended the lifetime to more than million shots and decreased the required laser threshold energy to less than 1 mu J. Novel type spectroscopic applications using the multiple wavelength laser array chip are also proposed and demonstrated. (c) 2005 The Optical Society of Japan.. |
| 200. | H. Watanabe, Y. Oki, M. Maeda, T. Omatsu, Waveguide dye laser including a SiO2 nanoparticle-dispersed random scattering active layer, Appl. Phys. Lett., 10.1063/1.1904717, 86, 15, Vol.86, 151123, 2005.04. |
| 201. | Y. Oki, H. Sato, A. Abe , H. Watanabe, M. Era, M. Maeda, Development of Distributed-feedback tunable blue-violet waveguide plastics laser based on fluorene compound, Jpn. J. Appl. Phys., 10.1143/JJAP.44.1759, 44, 4A, 1759-1763, Vol. 44. No. 4A, 2005.04. |
| 202. | Y Oki, H Sato, A Abe, H Watanabe, M Era, M Maeda, Development of distributed-feedback tunable blue-violet waveguide plastic laser based on fluorene compound, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 10.1143/JJAP.44.1759, 44, 4A, 1759-1763, 2005.04, The distributed feedback plastic lasers for blue-violet were developed. The developed fluorene molecules for electroluminescence devices were adopted and doped in poly(methymethacrylate: 2-hydroxyethylemethacryl ate). Laser operation was confirmed at a wavelength of about 410 nm using frequency-tripled and passively Q-switched Nd:Cr:YAG laser. A laser threshold of 70 nJ and the longest lifetime of 3000 shots were demonstrated.. |
| 203. | Waveguide dye laser including a SiO2 nanoparticle-dispersed random scattering active layer. |
| 204. | Y. Oki, M. Maeda, M. Tanaka, Development of integrated tunable laser system for laser spectroscopy, Molecular Crystals and Liquid Crystals, 10.1080/15421400490505875, 424, 55-63, Vol.424, No.17, pp.55--63, 2004.11. |
| 205. | Wavegiude dye laser including nano-size-particles doped active layer We have demonstrated a novel wavegiude dye laser including an active random scattering layer. The slope efficiency of 12.0% and the threshold energy of 0.34μJ were achieved, respectively.. |
| 206. | D. Zuo, Y. Oki, M. Maeda, Numerical Simulation of a Pulsed Laser Pumped Distributed-Feedback Waveguided Dye Laser by Coupled-Wave Theory, IEEE Journal of Quantum Electronics, 10.1109/JQE.2003.810272, 39, 5, 673-680, Vol.39, No.5, pp.673-680, 2003.05. |
| 207. | DL Zuo, Y Oki, M Maeda, Numerical simulantion of a pulsed laser pumped distributed-feedback waveguided dye laser by coupled-wave theory, IEEE JOURNAL OF QUANTUM ELECTRONICS, 10.1109/JQE.2003.810272, 39, 5, 673-680, 2003.05, A dynamic model of pulsed laser pumped distributed-feedback (DFB) waveguided dye laser based on a coupled-wave theory is described. Due to the periodical distribution of the intensities of pump I source and stimulated emission along the waveguide, the rate equations of the population densities are turned into the equations of the Fourier coefficients. Coupled-wave equations of optical fields are used to simulate the laser oscillation. Besides the temporal evolution of the output intensity, the spectra can also be obtained by the Fourier transform of the optical fields. Two different configurations. of the waveguided dye. laser, prefabricated DFB (mainly index coupling), first- and second-order holographic DFB (dynamic gain-coupling), are considered in the model. The simulation shows that: 1) the temporal waveforms of the holographic DFB consist of sharp spikes; 2) the broadened spectral widths resulted from the possible nonuniformities in propagation constant or grating period are less than 50 pm except for the second-order holographic DFB; and 3) strong parasitic oscillations can be observed in the second-order holographic DFB with terminal reflection. These results and the comparisons of some of them to the experiments are reported.. |
| 208. | Y. Oki, S. Miyamoto, M. Tanaka, D. Zuo, M. Maeda, Long Lifetime and High Repetition Rate Operation form Distributed Feedback Plastic Waveguided Dye Lasers, Optics Communications, 10.1016/S0030-4018(02)02125-9, 214, 1-6, 277-283, Vol.214, pp.227-283, 2002.12. |
| 209. | Y Oki, S Miyamoto, M Tanaka, DL Zuo, M Maeda, Long lifetime and high repetition rate operation from distributed feedback plastic waveguided dye lasers, OPTICS COMMUNICATIONS, 214, 1-6, 277-283, 2002.12, Long lifetime and high repetition rate laser operation was demonstrated from laser-dye-doped waveguides with distributed feedback (DFB) structures. The waveguides were fabricated with a spin-coating and lithography techniques, and DFB structure was written by an ultraviolet holography technique. A compact frequency-doubled Nd:YAG microchip laser was used as a pumping source, and the laser output wavelength range of 575-945 nm was obtained from 10 different kinds of laser-dye-doped plastic film and the laser performance was evaluated about 5 of them. Very low pumping energy requirement of around several muJ could extend the durabilities of the DFB dye-doped waveguides, and the lifetime of more than one million shots was obtained. Further a high repetition laser operation up to 1000 pps was demonstrated with an output energy stability of less than +/-0.5%. A palm-top size tunable laser is realized by this configuration. (C) 2002 Elsevier Science B.V. All rights reserved.. |
| 210. | Y Oki, K Aso, D Zuo, NJ Vasa, M Maeda, Wide-wavelength-range operation of a distributed-feedback dye laser with a plastic waveguide, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 10.1143/JJAP.41.6370, 41, 11A, 6370-6374, Vol.41, No.11A, pp.6370-6374, 2002.11, A compact distributed-feedback (DFB) dye laser with a plastic waveguide was developed. The DFB operation was attained by the interference of two pumping beams from a frequency-doubled pulsed Nd:YAG laser, and a wavelength range between 560 nm and 994 nm was continuously covered. The dye chip can instantaneously exchanged in any spectrum region. The threshold energy was decreased to the order of 100 muJ with the waveguide configuration. The maximum life of the dye chip was 10(6) shots.. |
| 211. | G. Ramos-Ortiz, Y. Oki, B. Domercq, B. Kippelen, Forster energy transfer from a fluorescent dye to a phosphorescent dopant: a co ncentration and intensity study, Phys. Chem. Chem. Phys, Vol.4, pp.4109-4114, 2002.08. |
| 212. | Y. Oki, T. Yoshiura, Y. Chisaki, M. Maeda, Fabrication of a Distributed-Feedback Dye Laser with a Grating Structure in its Plastic Waveguide, Appl. Optics, 10.1364/AO.41.005030, 41, 24, 5030-5035, Vol.41, No.24, pp.5030-5035, 2002.08. |
| 213. | G. Ramos-Ortiz, Y. Oki, B. Domercq, B. Kippelen, F{o}rster energy transfer from a fluorescent dye to a phosphorescent dopant: a concentration and intensity study, Phys. Chem. Chem. Phys, Vol.4, pp.4109-4114, 2002.08. |
| 214. | Y Oki, T Yoshiura, Y Chisaki, M Maeda, Fabrication of a distributed-feedback dye laser with a grating structure in its plastic waveguide, APPLIED OPTICS, 10.1364/AO.41.005030, 41, 24, 5030-5035, 2002.08, Two approaches of fabricating grating structures for waveguided plastic dye lasers are described and compared for lasing performance. Rhodamine6G-doped poly(methyl methacrylate) (PMMA) film on a PMMA substrate was used for the waveguide, and a distributed-feedback (DFB) laser operation with a single-propagation mode was demonstrated. The performances of both types of permanent grating structured DFB dye laser were better than those of a DFB dye laser on a plain waveguide with a dynamic grating formed by the interference of two pump beams. Wide tuning range is expected by use of a multistripe DFB laser with different grating pitches. (C) 2002 Optical Society of America.. |
| 215. | Y. Oki, S. Miyamoto, M. Maeda, N. J. Vasa, Multiwavelength Distributed-Feedback Dye Laser Array and its Application to Spectroscopy, Optics Letters, 10.1364/OL.27.001220, 27, 14, 1220-1222, Vol.27, No.14, pp.1220-1222, 2002.07. |
| 216. | Y Oki, S Miyamoto, M Maeda, NJ Vasa, Multiwavelength distributed-feedback dye laser array and its application to spectroscopy, OPTICS LETTERS, 10.1364/OL.27.001220, 27, 14, 1220-1222, 2002.07, A multiwavelength, multistripe tunable laser array is proposed, and its application to absorption spectroscopy is demonstrated. Laser waveguides doped with Rhodamine 6 G dye were integrated on a plastic chip, and simultaneous output at different wavelengths was obtained by use of a distributed-feedback technique. A very low threshold of 3 muJ was attained, and spectrally narrowed output ( |
| 217. | Y. Oki, S. Miyamoto, N. J. Vasa, M. Maeda, Novel Laser Spectroscopy Based on Multi-Wavelength and Multi-Striped Waveguided Solidstate Dye Laser, Technical Digest of CLEO/QELS, pp.213-214, 2002.06. |
| 218. | D. Zuo, D. Furukawa, Y. Oki, M. Maeda, Waveguided Dye Laser with Distributed Feedback, Proc. Int. Workshop on Informations and Electrical Engineering(IWIE), pp.199-204, 2002.05. |
| 219. | N. J. Vasa, A. Hatada, S. Nakazono, Y. Oki, M. Maeda, Feasibility of Nonlinear Raman Lidar Based on Stimulated Raman Gain Spectroscopy without a Tunable Laser, Appl. Optics, 10.1364/AO.41.002328, 41, 12, 2328-2332, Vol.41, No.12, pp.2328-1332, 2002.04. |
| 220. | NJ Vasa, A Hatada, S Nakazono, Y Oki, M Maeda, Feasibility of nonlinear Raman lidar based on stimulated Raman gain spectroscopy without a tunable laser, APPLIED OPTICS, 10.1364/AO.41.002328, 41, 12, 2328-2332, 2002.04, A novel technique of lidar for atmospheric gas detection by use of stimulated Raman gain spectroscopy without any tunable laser is proposed. Detection sensitivity and detectable range are estimated on the basis of the lidar equation for CO2, CH4, and H-2 in the atmosphere. The feasibility study clearly shows that the technique has a potential for application to lidar and that. in addition, the construction of the system is simpler than those of traditional differential absorption lidars. (C) 2002 Optical Society of America.. |
| 221. | Development of an Alternating Wavelength Controller for a Laser Rader for the Measurement of CO2 in the Atmosphere. |
| 222. | G. Ramos-Ortiz, Y. Oki, B. Domercq, B. Kippelen, F{o}rster Energy Transfer from a Fluorescent Dye to a Phosphorescent Dopant : a Concentration and Intensity Study, Technical Digest of 6th International Conference On Organics Nonlinear Optics (ICONO'6), pp.PS35, 2001.12. |
| 223. | N. J. Vasa, Y. Oki, T. Okada, M. Maeda, Development of All-Solid State Tunable Laser Sources for Spectroscopic Applications, Recent Res. Devel. Applied Phys., Vol.4, pp.77-85, 2001.10. |
| 224. | D. Zuo, N. J. Vasa, Y. Oki, M. Maeda, Numerical Simulation of Waveguided Distributed Feedback Dye Lasers by Coupled Mode Theory, Proc. Int. Symp. Laser - Aided Plasma Diagnostics, pp.265--270, 2001.09. |
| 225. | Y. Oki, T. Higotani, T. Takao, M. Maeda, Nano-Scale Solid Surface Analysis Using Laser Ablation Atomic Fluorescence Spectroscopy, Proc. Int. Symp. Laser - Aided Plasma Diagnostics, pp.328--333, 2001.09. |
| 226. | A. Hatada, S. Nakazono, N. J. Vasa, Y. Oki, M. Maeda, Proposal of Nonlinear Raman Lidar Based on Stimulated Raman Gain Spectroscopy without Tunable Laser, Technical Digest of CLEO Pacific-Rim2001, 170-171, pp.170--171, 2001.07. |
| 227. | S. Miyamoto, Y. Oki, S. Tokuyama, M. Maeda, Polymer-Based Solid-State Multi-Strip Dye Lasers for Laser Spectroscopy without Frequency Scanning, Technical Digest of CLEO Pacific-Rim2001, 214-215, pp.214--219, 2001.07. |
| 228. | T. Higotani, M. K. Kim, T. Takao, Y. Oki, M. Maeda, Nanometer-Scale Surface Element Analysis Using Laser Ablation Atomic Fluorescence Spectroscopy, Technical Digest of CLEO Pacific-Rim2001, 34-35, pp.34--35, 2001.07. |
| 229. | M. K. Kim, T. Higotani, T. Takao, Y. Oki, M. Maeda, Influence of Irradiation Wavelength on Atomic Emission Spectroscopy Using Laser Ablation, Jpn. J. Appl. Phys., 10.1143/JJAP.40.2556, 40, 4A, 2556-2557, Vol.40, No.4A, pp.2556--2557, 2001.04. |
| 230. | MK Kim, T Higotani, T Takao, Y Oki, M Maeda, Influence of irradiation wavelength on atomic emission spectroscopy using laser ablation, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 40, 4A, 2556-2557, 2001.04, In this study, the influence of laser wavelengths on atomic emission spectroscopy using laser ablation for samples (glass, polymer, Si, and Cu) has been investigated using 1064 ran and 266 mn pulses of a Q-switched Nd:YAG laser, The threshold fluence is decreased and the emission intensity is increased for UV laser ablation, compared with IR laser ablation. Simultaneous irradiation by both IR and UV pulses has also been found in decreasing the threshold and increasing the emission intensity.. |
| 231. | M. K. Kim, T. Takao, Y. Oki, M. Maeda, Thin-Layer Ablation of Metals and Silicon by Femtosecond Laser Pulses for Application to Surface Analysis, Jpn.J.Appl.Phys., 10.1143/JJAP.39.6277, 39, 11, 6277-6280, Vol.39, No.11, pp.6277--6280, 2000.11. |
| 232. | MK Kim, T Takao, Y Oki, M Maeda, Thin-layer ablation of metals and silicon by femtosecond laser pulses for application to surface analysis, JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 39, 11, 6277-6280, 2000.11, For the purpose of thin-layer surface analysis, comparison of laser ablation by 24 ns ArF laser pulses at 193 nm and that by 150 fs Ti:sapphire laser pulses at 780 nm for samples ranging from metals to semiconductors is reported. In contrast to nanosecond laser pulses, the ablation threshold for femtosecond laser pulses could be reduced significantly. In particular, the threshold for a Si sample was reduced to about one order of magnitude, and an ablation rate of 0.48 nm/shot was obtained at 5% above the threshold fluence. The root-mean-square (RMS) growth rate in the roughness of the ablated surface was 0.05 nm/shot. These results show the advantages of femtosecond laser ablation for trace element analysis of a wide range of materials, coupled with laser-induced fluorescence (LIF) spectroscopy.. |
| 233. | M. Maeda, Y. Oki, Y. Nonaka, S. Nakazono, Nonlinear Raman Spectroscopy without Tunable Laser and Application to Lidar, Proc. Conf. SPIE Int. Sympo. on Remote Sensing of the Atmosphere, Environment, and Space, 10.1117/12.417061, 4153, 30-41, pp.13, 2000.10. |
| 234. | N. J. Vasa, K. Saito, K. Ikuta, Y. Oki, M. Maeda, Development of a Compact Light Source at 1.67 Micrometer for Methane Leak Detection Using DIAL, Proc. Conf. SPIE Int. Sympo. on Remote Sensing of the Atmosphere, Environment, and Space, 10.1117/12.417081, 4153, 471-479, pp.14, 2000.10. |
| 235. | MAEDA M., Multi-stripe tunable waveguided DFB laser for New Type of Laser Spectroscopy, Technical Digest of CLEO/Europe 2000, 58, pp.58, 2000.09. |
| 236. | Y Oki, S Nakazono, Y Nonaka, M Maeda, Sensitive H-2 detection by use of thermal-lens Raman spectroscopy without a tunable laser, OPTICS LETTERS, 25, 14, 1040-1042, 2000.07, A new nonlinear Raman spectroscopy technique for trace-gas detection was proposed and demonstrated. The technique involved the use of a thermal-lens detection scheme to monitor thermal emission from the stimulated Raman process. We termed this technique thermal-lens Raman spectroscopy, and it was combined with a novel scheme involving a nonlinear Raman spectroscopy without a tunable laser. This technique was applied to detecting trace hydrogen molecules in the atmosphere by use of a pulsed Nd:YAG laser and a continuous-wave He-Ne probe laser. A detection limit of 9 parts in 10(6) was attained. (C) 2000 Optical Society of America OCIS codes: 170.5660, 300.6390, 290.5910, 190.4180, 350.6830.. |
| 237. | M. K. Kim, H. Ishii, T. Takao, Y. Oki, M. Maeda, Analysis of Trace Element in Solids by Using Laser Ablation Atomic Fluorescence Specrtosopy, Technical Digest Conf. Lasers and Electro-Optics CLEO/QELS 2000, pp.164, 2000.05. |
| 238. | 吉浦 豪, 苣木 雄一, 興 雄司[他], 導波型分布帰還固体色素レーザーのRGB領域発振, Research reports on information science and electrical engineering of Kyushu University, 10.15017/1515678, 5, 1, 141-146, Vol.5, No.1, pp.141--146, 2000.03, The laser operation of very compact tunable lasers based on the distributed feedback (DFB) dye lasers in plastic waveguide is evaluated. The tuning range is expanded to the RGB (Red-Green-Blue) region using only a frequency-tripled Nd:YAG laser pumping, and the tuning in each region is achieved by changing the interfering angle of the pump beam. This scheme is suitable for the integrated tunable lasers with some improvements.. |
| 239. | 興 雄司, 吉浦 豪, 松岡 孝義[他], 導波型固体色素レーザーへの分布帰還構造作製, Research reports on information science and electrical engineering of Kyushu University, 10.15017/1515677, 5, 1, 135-140, Vol.5, No.1, pp.135--140, 2000.03, A grating structure was fabricated on Rhodamine6G doped PMMA film using holographic exposure and wet-etching technique, and distributed feedback (DFB) laser operations were demonstrated on the waveguided solidstate dye laser film. The performances of the fabricated DFB dye laser were evaluated and compared with those of holographically pumped DFB dye laser, and an improvement of diffraction efficiency was obtained. The threshold fluence of 800μJ/cm^2 and energy of 40μJ were achieved, and the wavelength tuning was demonstrated using thermal control.. |
| 240. | M. Kim, H. Ishii, K. Taoka, Y. Oki, M. Maeda, Nanometer-Scale Surface Element Analysis in Polymers Using Laser Ablation Atomic Fluorescence Spectroscopy, J.Appl.Phys., 10.1063/1.371975, 87, 3, 1029-1033, Vol.87, No.3, pp.1029--1033, 2000.02. |
| 241. | K. Igarashi, M. Maeda, T. Takao, Y. Oki, H. Kusama, Dominant Factors of Preventing Rhodamine 6G form Dimer Formation in Aqueous Solutions, Bull.Chem.Soc.Jpn., 10.1246/bcsj.72.1197, 72, 6, 1197-1202, Vol.72, No.6, pp.1197--1202, 1999.10. |
| 242. | 生田 光輝, 工藤 務, 興 雄司[他], 漏洩メタン検知に用いる近距離高分解能1.67μmDIALシステム, Research reports on information science and electrical engineering of Kyushu University, 10.15017/1515803, 4, 2, 199-205, Vol.4, No.2, pp.199--205, 1999.09, A differential absorption lidar (light detection and ranging) system is developed as methane leakage detector using 1.67μm absorption band. A detection range of various 100m and 1000ppm•m is estimated by numerical calculation, and 30m resolution of detection is demonstrated experimentally. Since amplifier noise and telescope misalignment spoil the sensitivity and the range of the system, solutions are also proposed. Development of a compact optical parametric oscillator for a transmitter injection-seeded by a laser diode is also reported.. |
| 243. | 中川 潤, 津村 陽一郎, 勝俣 賢二, レーザレーダによる広域メタンガス漏洩検知技術の開発, 三菱重工技報, 36, 5, 274-277, Vol.36, No.5, pp.274--277, 1999.09. |
| 244. | M. Maeda, T. Okada, Y. Oki, N. J. Vasa, Y. Nakata, Very Compact Tunable Lasers form Visible to IR Region, Proc. Int. Sympo. Laser-Aided Plasma Diagnostics (LAPD), pp.357--363, 1999.09. |
| 245. | Y. Oki, J. Takafuji, M. Maeda, Nonlinear Raman Spectroscopies with Raman Shifter for Sensitive Gas Detection, Technical Digest Conf. Lasers and Electro-Optics （CLEO/Pacific Rim '99）, pp.1192--1193, 1999.09. |
| 246. | M. Maeda, Y. Oki, O. Yamashita, K. Furukawa, Distributed Feedback Laser Operation of Dye Doped Plastic Waveguide, Technical Digest Conf. Lasers and Electro-Optics （CLEO/Pacific Rim '99）, pp.682-683, 1999.09. |
| 247. | K. Ikuta, N. J. Vasa, Y. Oki, M. Maeda, M. Uchiumi, Differential Absorption Lidar at 1.67$mu$m for the Detection of Methane Gas Leakage, Technical Digest Conf. Lasers and Electro-Optics （CLEO/Pacific Rim '99）, pp.274--275, 1999.09. |
| 248. | M. K. Kim, H. Ishii, K. Taoka, Y. Oki, M. Maeda, Application of Laser Ablation Atomic Fluorescence Spectroscopy for Nanometer Solid Surface Analysis, Technical Digest Conf. Lasers and Electro-Optics （CLEO/Pacific Rim '99）, pp.1194-1195, 1999.09. |
| 249. | K. Ikuta, T. Kudo, N. Yoshikane, N. J. Vasa, Y. Oki, M. Maeda, Geometrical Form Factor Improvement for Receiving System of Infrared Lidar, Optical Review, 10.1007/s10043-999-0464-y, 6, 5, 464-470, Vol.6, No.5, pp.464--470, 1999.06. |
| 250. | A. Ikeda, T. Sadou, H. Nagashima, K. Kouno, N. Yoshikawa, K. Tsukamoto, Y. Kuroki, Electronic Properties of MOS Capacitor Exposed to Inductively Coupled Hydrogen Plasma, Thin Solid Films, 10.1016/S0040-6090(99)00062-0, 345, 1, 172-177, Vol.345, No.1, pp.172--177, 1999.06. |
| 251. | Kaoru Igarashi, Mitsuo Maeda, Takayuki Takao, Oki Yuji, Hideaki Kusama, Dominant factors of preventing Rhodamine 6G from dimer formation in aqueous solutions, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.72.1197, 72, 6, 1197-1202, 1999.06, Rhodamine 6G/water/alcohol or carboxylic acid systems were studied. Rhodamine 6G molecules, which tend to associate into nonfluorescent dimers in aqueous solution, were prevented from dimerization by mixing them with organic compounds. It was found that additives with smaller dielectric constants prevented the dye molecules from associating to effectively form dimers. It was found that 2-butanol and isobutyric acid were the most effective additives for dissolving Rhodamine 6G dimer and that the amount demanded to obtain the necessary concentration of monomer in aqueous solution was less than 10%.. |
| 252. | N. J. Vasa, K. Ikuta, Y. Oki, M. Maeda, Remote Monitoring of Methane Gas Leakage at 1.67$mu$m by Differential Absorption Lidar, Technical Digest Conf. Lasers and Electro-Optics （CLEO'99）, pp.158, 1999.05. |
| 253. | Y. Oki, J. Takafuji, M. Maeda, Nonlinear Raman Spectroscopies with Raman Shifter for Sensitive Gas Detection, Technical Digest Conf. Lasers and Electro-Optics （CLEO'99）, pp.94, 1999.05. |
| 254. | 川田 則幸, 興 祐司, 高藤 潤哉, 前田 三男, 可変波長レーザーを用いない非線形ラマン分光法による大気中微量分子の検知, レーザー研究, 10.2184/lsj.27.194, 27, 3, 194-198, Vol.27, No.3, pp.194--198, 1999.03, A new technique for nonlinear Raman spectroscopy is proposed and discussed theoretically in terms of the detection of gas molecules in atmospheric pressure. In the proposed scheme, only a pulsed Nd: YAG laser is used as a pumping source, and instead of a tunable laser, a Raman shifter filled with the sametype of gas as that to be detected automatically generates the Raman shifted radiation. The detection limits of H2for SRGS (Stimulated Raman Gain Spectroscopy), PARS (Photo-Acoustic Raman Spectroscopy), and CARS (Coherent Anti-Stokes Raman Spectroscopy) are demonstrated experimentally, and the ppm order detection limit can be achieved by PARS. Although the sensitivity of CARS is smaller than that of PARS, the signal tonoise ratio in higher concentration is more effective.. |
| 255. | Y. Oki, N. Kawada, Y. Abe, M. Maeda, Nonlinear Raman Spectroscopy without Tunable Laser for Sensitive Gas Detection in the Atmosphere, Optics Communication, 10.1016/S0030-4018(98)00660-9, 161, 1-3, 57-62, Vol.161, pp.57--62, 1999.02. |
| 256. | K. Ikuta, N. Yoshikane, N. J. Vasa, Y. Oki, M. Maeda, M. Uchiumi, Y. Tsumura, J. Nakagawa, N. Kawada, Differential Absorption Lidar at 1.67$mu$m for Remote Sensing of Methane Leakage, Jpn.J.Appl.Phys., 10.1143/JJAP.38.110, 38, 1A, 110-114, Vol.38, No.1A, pp.110--114, 1999.01. |
| 257. | N. Kawada, Y. Oki, Y. Abe, M. Maeda, Inflammable Gas Detection in the Atmosphere Using Photoacoustic and Cherent-Anti-Stokes Raman Spectroscopy without a Tunable Laser, Review of Laser Engineering, Vol.26, No.別冊, pp.133--137, 1998.10. |
| 258. | M. Maeda, Y. Oki, K. Ohno, Compact Ultrashort-Pulse Generator Using an Integrated Dye Laser, Review of Laser Engineering, Vol.26, No.別冊, pp.104--107, 1998.10. |
| 259. | Y. Oki, M. Maeda, Y. Abe, Sensitive Gas Detection in the Atmosphere with Newtype of Photo-Acoustic Raman and Coherent Anti-Stoke Raman Spectroscopy, Technical Digest. Conf. Laser Electro-Optics （CLEO'98）, pp.83, 1998.05. |
| 260. | K. Ikuta, Y. Oki, N. J. Vasa, M. Maeda, M. Uchiumi, Remote Sensing of Methane Differential Absorption Lidar at 1.67$mu$m, Technical Digest. Conf. Laser Electro-Optics （CLEO'98）, pp.129, 1998.05. |
| 261. | Y. Oki, T. Takao, T. Nomura, M. Maeda, UV-Laser Ablation Spectroscopy in Element Analysis of Solid Surface, Optical Review, 10.1007/s10043-998-0242-2, 5, 4, 242-246, Vol.5, No.4, pp.242--246, 1998.04. |
| 262. | Yuji Oki, Kenji Matsunaga, Takumi Nomura, Mitsuo Maeda, Removal of thin layer for trace element analysis of solid surface in subnanometer scale using laser-ablation atomic fluorescence spectroscopy, Applied Physics Letters, 10.1063/1.120215, 71, 20, 2916-2918, 1997.11, Laser-ablation atomic fluorescence (LAAF) spectroscopy has extremely high sensitivity in the analysis of trace elements. Using the ArF laser-ablation technique at a wavelength of 193 nm, removal of thin surface layer of the order of 1.1 nm/shot for the first 50 shots and 0.4 nm/shot after that is demonstrated for a solid glass sample. A constant fluorescence signal from Na atoms is obtained for each shot. There is a possibility of determining the depth distribution of an element with subnanometer resolution by applying LAAF spectroscopy. © 1997 American Institute of Physics.. |
| 263. | Yuji Oki, Koichiro Furukawa, Mitsuo Maeda, Extremely sensitive Na detection in pure water by laser ablation atomic fluorescence spectroscopy, Optics Communications, 10.1016/S0030-4018(96)00465-8, 133, 1-6, 123-128, 1997.01, An extremely sensitive trace element detection technique in water is proposed and demonstrated, in which the excimer laser ablation is used to generate a densely atomized plume and the generated atoms are detected by sensitive laser-induced fluorescence (LIF) spectroscopy with a CW dye laser. Very strong LIF signal is detected without any interference of the plume radiation for 1 ppt, 10 μI Na water solution. A detection limit less than 0.1 ppt or 1 fg can be attained by this scheme.. |
| 264. | 五十嵐, 前田三男, 高尾隆之, 内海通弘, 興雄司, 島本幸次郎, Operation of Rhodamine 6G Dye Laser in Water Solution, Jp. J. Appl. Phys., 10.1143/JJAP.34.3093, 34 Pat1, 6A, 3093-3096, 1995.06, The ethanolic solution of Rhodamine 6G is used for dye lasers in the atomic vapor laser isotope separation (AVLIS) system. However, the water solution is preferable from the standpoint of easy treatment and safety. In this paper, we systematically investigated the laser efficiency of a Rhodamine 6G dye laser pumped by a frequency-doubled Nd:YAG laser, for various water-based solutions with surface-active agents and alcohols. By adding an appropriate amount of surface-active agent (Triton X or Emulgen) or alcohol (ethanol or propanol), we obtained almost the same level of laser efficiency as in the pure ethanolic solution. The improvement in the laser efficiency with these additives was attained by the deaggregation of nonradiative dimers. It was also confirmed that the water-based solution showed better performance against thermal distortion than the ethanolic solution, and was suitable for copper vapor laser (CVL) pumping.. |
| 265. | Trace Element Analysis in Pure Water by Laser Ablation Atomic Fluorescence Spectroscopy We have proposed scheme to detect trace elements analysis in pure water, in which the excimer laser ablation technique is combined with the laser induced atomic fluorescence spectroscopy. Theoretical estimation predicts very high sensitivity of this method, because the excimer laser ablation can generate high density atoms in the low background radiation. Sensitive detection of Na atoms is demonstrated by using this method in low pressure helium, and detection limit of 1.7 ppt is obtained. The same experiment is made under the open air condition, by using the ablation in a He supersonic jet and the detection limit less than 1ppb is attained.. |
| 266. | Yuji Oki, Nobutaka Kidera, Mitsuo Maeda, Enhancement of sensitivity of optogalvanic spectroscopy in a flame by laser ionization, Optics Communications, 10.1016/0030-4018(94)90179-1, 110, 1-2, 105-108, 1994.08, In usual optogalvanic spectroscopy in a flame, the signal is obtained by thermal ionization of selectively excited species. The optogalvanic signal in a flame was remarkably enhanced by selective multi-step photo-ionization, when an intense UV laser beam was applied into the flame. The enhancement factor exceeded 100 and a detection limit of 5 ppt (pg/ml) was obtained, when this technique was applied for tracing atomic Ca in water. © 1994.. |
| 267. | Yuji Oki, Tomohiro Tani, Nobutaka Kidera, Mitsuo Maeda, Trace element analysis by laser ablation atomic fluorescence spectroscopy, Optics Communications, 10.1016/0030-4018(94)90429-4, 110, 3-4, 298-302, 1994.08, A very sensitive method to make a trace element analysis in pure water, the laser ablation atomic fluorescence (LAAF) spectroscopy, is proposed and demonstrated, where the atomic detection by laser induced fluorescence (LIF) is combined with excimer laser ablation atomizing. A theoretical calculation predicts that the detection limits of 0.01-0.1 ppt can be expected in an ideal case. A detection limit of 1.7 ppt or 20 fg was experimentally obtained for Na. © 1994.. |
| 268. | Yuji Oki, Eiji Tashiro, Mitsuo Maeda, Chikahisa Honda, Yoshio Hasegawa, Hiroshi Futami, Jun Izumi, Keiichi Matsuda, Sensitive Detection of Trace Elements in Pure Water by Laser-Induced Atomic Fluorescence Spectroscopy in Microwave Discharge Atomization, Analytical Chemistry, 10.1021/ac00063a028, 65, 15, 2096-2101, 1993.08, Sensitive detection of trace elements in pure water using laser-induced fluorescence (LIF) spectroscopy with a new flameless atomizer is reported. The atomizer is a combination of a microwaveinduced plasma in atmospheric helium and a filament vaporization system. A newly developed pulsed dye laser, which was rapidly and automatically accessible over a wide spectral range from 220 to 740 nm, was used as the laser source. Sixteen elements were analyzed by this system, and for most of these, the detection limit was less than 1 ng/mL, which was better than those obtained by flame LIF analysis. The analytical curve and the saturation curve were measured for each element, and various factors which affect the detection sensitivity are theoretically discussed. © 1993, American Chemical Society. All rights reserved.. |
| 269. | 内海通弘, 岡田龍雄, 興雄司, 前田三男, Application of a Selective Laser Ionization Photodetector for Detection of Raman Scattering in Flames, Optics Communications, 98, 1-3, 67-71, 1992.10. |
| 270. | Yuji Oki, Hisanori Uda, Chikahisa Honda, Mitsuo Maeda, Jun Izumi, Takashi Morimoto, Masazumi Tanoura, Laser-Induced-Fluorescence Detection of Sodium Atomized by a Microwave-Induced Plasma with Tungsten Filament Vaporization, Analytical Chemistry, 10.1021/ac00206a006, 62, 7, 680-683, 1990.03, The laser-induced-fluorescence (LIF) technique is applied to the detection of Na atoms In pure water for a concentration range down to pg/cm3. Na compounds are dissociated by a microwave-Induced plasma of He with a tungsten filament vaporization system. Calibrating the absolute density at the observing region, the efficiency of this atomizer Is estimated. It Is shown that the atomizer can generate high atomic densities by filament heating. For example, the number density reaches 107 atoms/cm3 for a 10-μL sample of 1 pg/cm3. © 1990, American Chemical Society. All rights reserved.. |
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