Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Yuji Oki Last modified date:2021.07.20

Professor / Integrated Electronics / Department of Electronics / Faculty of Information Science and Electrical Engineering


Papers
1. 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.
2. Abdul NASIR; Yuya MIKAMI; Rui YATABE; Hiroaki YOSHIOKA; Nilesh J. 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, 592-602, 2021.03, Materials with biomolecule-compatible functional groups are desirable for the fabrication of microdisk lasers used in bio-sensing applications. In this study, a microdisk laser was fabricated using a low-viscosity hyper branched polymer FC-V-50 using ink-jet printing, and was surface-modified at room temperature within a relatively short time compared to conventional methods. The carboxyl functional group of the FC-V-50 polymer was used for surface modification and biotinylation. The adsorption characteristics of the microdisk laser were evaluated using bovine serum albumin, avidin, and streptavidin. This study reports the first demonstration of label-free biosensing using the FC-V-50 polymer-based microdisk laser..
3. 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..
4. 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.
5. Abdul Nasir, Rui Yatabe, Yuya Mikami, Hiroaki Yoshioka, Nilesh J. Vasa, Yuji Oki, Ink-jet printed, blended polymer-based microdisk resonators for controlling non-specific adsorption of biomolecules, OPTICS LETTERS, 10.1364/OL.412993, 46, 2, 262-265, 2021.01.
6. 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..
7. 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..
8. 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..
9. 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.
10. 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..
11. 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..
12. 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..
13. 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..
14. 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.
15. 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.
16. 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.
17. 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), https://doi.org/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< ttable). The ANOVA test (F test) results showed that the Fcount value is less than Ftable so that the results of Cr(VI) analysis in the standard solution and liquid waste samples measured by three instrumentations. Thus, it was concluded that portable instrumentations was good and gives the same quality as conventional instrumentations (UV-Vis and ICP AES)..
18. 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.
19. 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.
20. 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..
21. 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..
22. 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.
23. 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..
24. 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..
25. 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..
26. 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, http://dx.doi.org/10.13005/ojc/350105, 35, 1, 49-55, 2019.01, [URL].
27. 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..
28. 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.
29. 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..
30. 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..
31. 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..
32. 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..
33. 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..
34. 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..
35. 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..
36. 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..
37. 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..
38. 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..
39. 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..
40. 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..
41. 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..
42. 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..
43. 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..
44. 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)..
45. 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..
46. 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..
47. 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..
48. 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..
49. 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..
50. 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..
51. 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..
52. 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.
53. 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.
54. 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.
55. 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.
56. 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..
57. 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..
58. 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..
59. 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..
60. 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.
61. 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.
62. 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..
63. 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.
64. 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.
65. 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..
66. 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..
67. 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.
68. Yuji Oki, Tomoya Ohta, Hiroaki Yoshioka, 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, 2013.10.
69. 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].
70. 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..
71. 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..
72. 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..
73. 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.
74. 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.
75. 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.
76. 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.
77. 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.
78. 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.
79. 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.
80. 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.
81. Hiroyuki Kubota, Soichiro Oomi, Hirofumi Watanabe and 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.
82. 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.
83. 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.
84. 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.
85. 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.
86. 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.
87. 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.
88. 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.
89. 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.
90. 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.
91. 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.
92. 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.
93. 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.
94. 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.
95. 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.
96. 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.
97. 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.
98. 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.
99. 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.
100. 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.
101. 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.
102. 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.
103. 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.
104. 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.
105. 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.
106. 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.
107. Noriyuki KAMOGAWA , Shusaku KATAOKA, Koichi SANADA, Masamitsu TANAKA, Hirofumi WATANABE, Development Thermo-Optical Quasi-Mode-Coupling DFB Dye Laser with Pen-Drawing Fabrication, The 6th Asia Pacific Laser Symposium, pp.54, 2008.01.
108. Shusaku KATAOKA, Noriyuki KAMOGAWA , Masamitsu TANAKA, Hirofumi WATANABE, Kenichi YAMASHITA, Masaya MIYAZAKI, Satoru KUHARA and 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.
109. 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.
110. 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.
111. 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.
112. 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.
113. 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.
114. 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.
115. 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.
116. 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.
117. 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.
118. 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.
119. 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.
120. 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.
121. 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.
122. 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.
123. 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.
124. 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.
125. 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.
126. 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.
127. 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.
128. 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.
129. 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.
130. 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.
131. 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.
132. 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.
133. 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.
134. Y. Oki, K. Aso, D. Zuo, N. J. Vasa, M. Maeda, Wide-Wavelength-Range Operation of a Distributed-Feedback Dye Laser with a Plastic Waveguide, Jpn. J. Appl. Phys., 10.1143/JJAP.41.6370, 41, 11A, 6370-6374, Vol.41, No.11A, pp.6370-6374, 2002.11.
135. 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.
136. 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.
137. 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.
138. 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.
139. 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.
140. 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.
141. 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.
142. 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.
143. 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.
144. 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.
145. 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.
146. 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.
147. 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.
148. 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.
149. 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.
150. 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.
151. 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.
152. 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.
153. M. Maeda, Y. Oki, T. Yoshiura, Y. Chisaki, Multi-Stripe Tunable Waveguide DFB Laser for New Type of Laser Spectroscopy, Technical Digest Conf. CLEO/Europe-IQEC 2000, pp.58, 2000.09.
154. 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.
155. 吉浦 豪, 苣木 雄一, 興 雄司, 松岡 孝義, 前田 三男, 導波型分布帰還固体色素レーザーのRGB領域発振, 九大システム情報科学研報, Vol.5, No.1, pp.141--146, 2000.03.
156. 興 雄司, 吉浦 豪, 松岡 孝義, 苣木 雄一, 山下 治, 前田 三男, 導波型固体色素レーザーへの分布帰還構造作製, 九大システム情報科学研報, Vol.5, No.1, pp.135--140, 2000.03.
157. 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.
158. 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.
159. 生田 光輝, 工藤 務, 興 雄司, バサ ニレシ, 前田 三男, 中川 潤, 漏洩メタン検知に用いる近距離高分解能1.67$mu$m DIAL システム, 九大システム情報科学研究科報告, Vol.4, No.2, pp.199--205, 1999.09.
160. 中川 潤, 津村 陽一郎, 勝俣 賢二, 前田 三男, 興 雄司, 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, Vol.36, No.5, pp.274--277, 1999.09.
161. 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.
162. 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.
163. 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.
164. 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.
165. 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.
166. 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.
167. 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.
168. 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.
169. 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.
170. 川田 則幸, 興 雄司, 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, Vol.27, No.3, pp.194--198, 1999.03.
171. 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.
172. 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.
173. Y. Oki, K. Ohno, M. Maeda, Tunable Ultrashort Pulse Generation form a Wave-guided Laser with Premixed-Dye-Doped Plastic Film, Jpn. J. Appl. Phys., 10.1143/JJAP.37.6403, 37, 12A, 6403-6407, Vol.37, No.12A, pp.6403--6407, 1998.12.
174. 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.
175. 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.
176. 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.
177. 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.
178. 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.