Language：English   Publishing type：Research paper (scientific journal)  

Language：English  

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DOI： 10.1016/S0030-4018(02)02125-9

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1364/AO.41.005030

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1364/OL.27.001220

Language：English  

Language：Japanese  

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1364/AO.41.002328

Language：Japanese  

Development of an Alternating Wavelength Controller for a Laser Rader for the Measurement of CO2 in the Atmosphere

Language：English  

Language：English  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1143/JJAP.40.2556

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1143/JJAP.39.6277

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1117/12.417061

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1117/12.417081

Language：English  

Multi-Stripe Tunable Waveguide DFB Laser for New Type of Laser Spectroscopy

Language：English  

Language：English  

導波型分布帰還固体色素レーザーのRGB領域発振

DOI： 10.15017/1515678

Language：English  

導波型固体色素レーザーへの分布帰還構造作製

DOI： 10.15017/1515677

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.371975

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1246/bcsj.72.1197

Language：English  

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

DOI： 10.15017/1515803

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English  

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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

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10043-999-0464-y

Language：English  

DOI： 10.1016/S0040-6090(99)00062-0

Language：English  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English  

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
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.

DOI： 10.2184/lsj.27.194

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/S0030-4018(98)00660-9

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1143/JJAP.38.110

Language：English  

Publisher：Optical Materials Express  

We incorporate a passive wedge-shaped organic microdisk supporting spatially separated whispering gallery modes into an SU-8 photonic integrated circuit (PIC) by using direct inkjet printing. This innovative method allows the mixing of multiple organic materials, enabling tunability of the refractive index of microdisks, thereby overcoming limitations of single-material resonators from conventional lithography. In this study, the microdisk resonator, with a refractive index matching that of SU-8 by mixing hyperbranched polymers, is mounted horizontally to an optical waveguide, achieving directional coupling between the microdisk and PIC at a wavelength of 1550 nm. Geometrical conditions for successful coupling were obtained by measuring the cross-sectional profile of the fabricated structure's surface via atomic force microscopy, determining ways to adjust the coupling efficiency.

DOI： 10.1364/OME.528582

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Scopus

Publisher：CLEO: Science and Innovations, CLEO: S and I 2024 in Proceedings CLEO 2024, Part of Conference on Lasers and Electro-Optics  

An Al-doped 4H-SiC device exhibits a large Verdet constant at a specific wavelength and polarization state via DPP-assisted annealing under the corresponding conditions. Thus, it can function as a novel MO-SLM for high-performance spectroscopic systems.

Scopus

Publisher：CLEO: Science and Innovations, CLEO: S and I 2024 in Proceedings CLEO 2024, Part of Conference on Lasers and Electro-Optics  

We successfully integrated a printed, wedge-shaped microdisk resonator into a photonic circuit, allowing coupling of spatially separated whispering gallery modes into an SU-8 ridge waveguide and interfacing with integrated optical circuits.

Scopus

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023  

Optical microcavities are attractive with the generation of whispering gallery mode (WGM), while the high-Q cavity contains numerous degenerate WGMs with varying orbital angular momenta, which can result in instability of laser oscillation. The incorporation of gratings with higher-order Bragg diffraction patterns is often utilized in conjunction with microcavities to enhance coupling efficiency between incident light and WGMs, and to break degeneracy. Although such functional microcavities are commonly fabricated via top-down methods such as photolithography as one-off pieces, utilizing bottom-up methods such as microdispensing is preferable when orienting towards photonic integrated circuits. However, the conventional dispensing method is quite difficult to make the functional microcavity because the grating period used in visible light or optical telecommunication wavelength bands becomes smaller than 1 µm that is almost the smallest size of microdispensed structure [1]. To meet this size constraint, nanodispensing technology is proposed in recent years, which utilizes the precision of force-controlled positioning in atomic force microscopy (AFM) in conjunction with the versatility of fluidics, thereby enabling the creation of functional and topographical features on a submicrometer scale [2]. In this work, we surmount the obstacle of the 1 µm size constraint by demonstrating the fabrication of second order diffraction grating patterns on Si3N4 optical microring (n = 2.04 at 1550 nm) via the utilization of nanodispensing technique.

DOI： 10.1109/CLEO/EUROPE-EQEC57999.2023.10232309

Scopus

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023  

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.

DOI： 10.1109/CLEO/EUROPE-EQEC57999.2023.10232613

Scopus

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023  

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.

DOI： 10.1109/CLEO/EUROPE-EQEC57999.2023.10232578

Scopus

Language：English   Publishing type：Research paper (international conference proceedings)  

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.

DOI： 10.1002/lpor.202200874

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Optica Publishing Group  

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

DOI： 10.1364/AO.486863

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Language：English   Publishing type：Research paper (scientific journal)  

Pneumatically Tunable Droplet Microlaser
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.

DOI： 10.1002/lpor.202200874

Language：Others   Publishing type：Research paper (scientific journal)   Publisher：Experimental Cell Research  

Photo-functionalization of titanium orthopedic/prosthetic implants using ultraviolet illumination is known to improve osteogenesis. Therefore, in this study, we aimed to examine the influence of vacuum ultraviolet (VUV)-treated titanium surfaces on osteoblast cell adhesion, activity, and differentiation. Osteoblastic cells were cultured on titanium substrates treated with various VUV treatment conditions (0, 6.2, 18.7, and 37.4 J/cm2) and their behavior was evaluated. The results revealed that cell adhesion was increased whereas cell activity and differentiation ability were decreased upon cell culture on VUV-treated substrates. In particular, cell activity and differentiation ability were dramatically suppressed with 18.7 J/cm2 VUV irradiation. Within the limitations of this cell-based experiment, we clarified the VUV treatment conditions in which cell adhesion was improved but cell activity and differentiation ability were suppressed. These results indicate that VUV-treatment can be used to influence cell growth properties and can be used to accelerate or suppress cell differentiation on implant substrates.

DOI： 10.1016/j.yexcr.2021.112944

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Language：English   Publishing type：Research paper (international conference proceedings)  

Other Link： https://www.jstage.jst.go.jp/article/jceeek/2022/0/2022_222/_pdf/-char/en

Language：English   Publishing type：Research paper (international conference proceedings)  

Other Link： https://www.jstage.jst.go.jp/article/jceeek/2022/0/2022_218/_pdf

Language：English   Publishing type：Research paper (international conference proceedings)  

Other Link： https://www.jstage.jst.go.jp/article/jceeek/2022/0/2022_220/_pdf

Language：English  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/adpr.202200018

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/adpr.202200018

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： https://doi.org/10.1364/CLEOPR.2022.CThP1G_05

Other Link： https://doi.org/10.1364/CLEOPR.2022.CThP1G_05

Language：Others   Publishing type：Research paper (scientific journal)   Publisher：Optical Materials Express  

An improved random walk scattering model that can be used for soft scattering based on the dispersion of the refractive index difference was developed. This model improves on previous models by introducing a medium thickness parameter and can explain the spectral performance of transparent/diffusive materials with different scatterer concentrations and thicknesses, as well as determine the optimal narrowing conditions for the bandpass spectra by combining Rayleigh-Gans-Debye and Hulst approximation calculations. Guided by the theory, transparent/diffusive media based on CaF2 particles suspended in a PDMS (polydimethylsiloxane) matrix were investigated. Disordered micron-sized CaF2 particles with a narrowed particle distribution were obtained by precipitation and centrifugal separation of ultra-pure milled CaF2 particles to remove the fractions smaller than 1 µm and larger than 20 µm, with removal rates of approximately 75% and 100%, respectively. Consequently, a diffuser material with a high (80 wt.%) concentration CaF2 particles dispersed in a low-viscosity PDMS matrix was successfully fabricated, which exhibited an effective transmittance bandwidth as low as 12 nm FWHM (full width at half maximum). Moreover, different bandpass filter diffuser devices with transmission peaks at 248, 257, and 272 nm were obtained by adjusting the PDMS matrix material. In particular, the 257 nm transmission peak filter diffuser exhibited a true narrow bandwidth of 9 nm in an integrated module containing a UV LED (ultraviolet light-emitting diode).

DOI： 10.1364/OME.447592

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Optical Society  

DOI： 10.1364/ome.446342

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Language：Japanese  

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

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Others   Publishing type：Research paper (scientific journal)  

In this study, we demonstrated an accurate estimation of the refractive index in nanoporous structures using a novel hybrid simulation method that combines electromagnetic field analysis and ray tracing based on wave optics and ray optics. A novel theoretical model for the refractive index in a nanoporous structure was developed using a simulation of the effective medium approximation (EMA) and screening effect with consideration of polarization dependence. The optical properties were then experimentally evaluated on aggregates of silica nanoparticles. Based on the measured properties, nanoparticles were predicted to have sufficient transparency for the optical cavity. A nanoporous microdisk laser was thus fabricated with laser dye to demonstrate that the nanoporous microdisk was capable of lasing. The microdisk functioned sufficiently as an optical cavity and had well-matched characteristics. This study provides a novel viewpoint of polarization dependence to estimate the refractive index of nanoporous materials by combining numerical simulations and experiments.

DOI： 10.1364/OME.434394

Language：Japanese  

Direct printing of Microdisk into High Transparency Nanoporous SiO₂ Film

DOI： 10.11527/jceeek.2021.0_357

Language：Others   Publishing type：Research paper (scientific journal)  

Biopolymers, which are organic macromolecules produced by living systems, are promising materials in terms of biodegradability and sustainability. However, in the field of optical sensing, most devices or their elements still rely on synthetic inorganic or organic compounds. In this study, we successfully transform pristine silk fibroin (SF), a naturally abundant and eco-friendly material, into discrete, well-defined microspherical particles that function as an active optical resonator for precise moisture sensing over a wide humidity range. The SF self-assembles into microspherical particles upon water-in-oil emulsification. When being photoexcited, the SF microspheres, doped with a fluorescent ionic dye, display whispering gallery mode (WGM) resonant luminescence. Because of their excellent hygroscopic properties, the SF microspheres expand in size as the surrounding humidity is increased, and the WGM resonant peaks exhibit a red shift with a linear relation to the surrounding humidity over a wide humidity range of up to 95 percent relative humidity (%RH) with a sensitivity as high as 187 pm/%RH. Furthermore, the SF microsphere works as a laser resonator upon femto-second pumping. The fully natural microspheres as presented in this work serve as sustainable and environmentally friendly optical resonators and sensors. This journal is

DOI： 10.1039/d1qm00451d

Language：Others   Publishing type：Research paper (scientific journal)  

This publisher's note contains corrections toOpt. Lett. 46, 262 (2021).

DOI： 10.1364/OL.433647

Language：Others   Publishing type：Research paper (scientific journal)  

We report a method to dynamically control the surface of gallium-based liquid metal to switch between reflective/diffusive states by removing/depositing oxide films via electrochemical redox reactions. Electrochemical oxidation deposits rough surface oxides that are optically diffusive. Electrochemical reduction returns the metal to a pristine, smooth, and reflective state. This switching is achieved using only ±1.4V. In addition, a meniscus of liquid metal can be pumped to switch between concave/convex shapes. This work expands the range of optical applications of dynamic liquid metal surfaces.

DOI： 10.1364/OME.425432

Language：English  

DOI： 10.1016/j.optmat.2021.111073

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1364/ome.415000

Language：English  

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.

DOI： 10.1117/12.2581237

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：English  

Language：English  

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.

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1364/ol.412993

Language：English  

DOI： 10.1117/12.2582700

Language：English  

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.

DOI： 10.1016/j.optcom.2020.126339

Language：Japanese  

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.talanta.2020.121102

Language：Others   Publishing type：Research paper (scientific journal)  

A flow enzyme-linked immunosorbent assay (ELISA) method based on light absorption by enzymatically generated aniline oligomer in the presence of horseradish peroxidase (HRP), H O , and aniline is proposed. Aniline oligomer is rapidly formed through the polymerization reaction via the enzymatic reaction, and its fast reaction rate is beneficial for flow ELISA. An anti-3-phenoxybenzoic acid monoclonal antibody (mAb) was produced by mice, and was used for the flow competitive ELISA for the determination of 3-phenoxybenzoic acid (3PBA), which was performed on an acrylic plate having a Y-shaped channel. ABS resin beads (d = 1 mm) were filled in the channel to increase the surface area for the adsorption of the mAb. A clank-type detection chamber (optical length: 1 cm) made of polydimethylsiloxane (PDMS) containing carbon black, which can significantly decrease light scattering, was fabricated with a 3D printer. The PDMS detection chamber was connected to the outlet of the acrylic flow chip with a tube. A blue LED was used as a light source for the flow ELISA. The inhabitation concentration at 50% and the detection range (absorbance change from 90 to 10%) for the proposed flow competitive ELISA were 0.5 ppm and 0.05–5 ppm, respectively. We also performed the flow competitive ELISA in an artificial and real urine, and no significant matrix effect of the urine samples on the ELISA was found. 2 2

DOI： 10.1016/j.talanta.2020.121102

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/j.microc.2020.104936

Language：English  

Language：Japanese  

Development of integrated spectral filter that down converts specific ultraviolet wavelength (II)

DOI： 10.11527/jceeek.2020.0_100

Language：Japanese  

ナノポーラス薄膜への光導波路構造の直接

Language：Others   Publishing type：Research paper (scientific journal)  

© 2020 Elsevier B.V. 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.

DOI： 10.1016/j.microc.2020.104897

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.microc.2020.104936

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/j.microc.2020.104897

Language：English  

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.

DOI： 10.1364/CLEOPR.2020.C7H_6

Language：Others   Publishing type：Research paper (other academic)  

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.

DOI： 10.1364/CLEOPR.2020.C2D_2

Language：English   Publishing type：Research paper (international conference proceedings)  

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.

DOI： 10.1364/CLEOPR.2020.C2D_2

Language：English  

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.

DOI： 10.1364/CLEOPR.2020.C7H_3

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1364/AO.396061

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/AO.396061

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1364/CLEO_AT.2020.AW3K.5

Language：Others   Publishing type：Research paper (other academic)  

Fluorinated hyper branched polymer based active microdisk was fabricated by ink-jet printing method. The carboxyl functional group of the polymer was used for the biotinylation of microdisk and then adsorption characteristics of avidin were evaluated.

DOI： 10.1364/CLEO_AT.2020.AW3K.5

Language：English  

DOI： 10.1364/CLEO_AT.2020.JTu2F.6

Language：English  

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).

DOI： 10.4028/www.scientific.net/KEM.840.406

Other Link： https://www.scientific.net/KEM.840.406?fbclid=IwAR2M_DpWXW8vXnFkrGtVEo3MTf2De1tCthJozp-Uq_7ONfxZxOVMdmqGjrY#.XqeGpAjpQTc.facebook

Language：Others  

Language：English  

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.

Language：English  

Language：Others  

Language：English  

Language：English  

Language：English  

Language：Japanese  

Language：Japanese  

2
九大シ情 ○

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.5118812

Language：Others   Publishing type：Research paper (scientific journal)  

© 2019 Author(s). The current trend for analytical systems and devices is to be small, portable, and low in cost because of the flexibility required to ensure their availability for on-site measurement applications. Using the concept of silicone optical technology (SOT), we propose a fully flexible analytical system, and digital fabrication of a compact optical module for flow-injection analysis (FIA) is demonstrated. A simple structure composed of a transparent polydimethylsiloxane (PDMS) optical core with a carbon black-dispersed PDMS cladding acts as a tiny but straightforward optical filter and shows an ability to trap light at tilted incidence; this structure is embedded on a silicone 3D-printed optical module via a simple injection and coating method. The coating properties, the optical trapping performance, and the cross talk test performance of the device were evaluated. The SOT-FIA optical module successfully demonstrated a 99.8% undesired light trapping performance; cross talk of less than 0.5% was observed, illustrating the low-noise detection performance of the SOT-FIA optical system. Colorimetric determination of iron in natural water samples demonstrated excellent linearity, a wide chemical analysis range, and good percentage recovery performance. The results of the determination in real water samples using the proposed SOT-FIA optical device agreed well with the results from the conventional spectrophotometric method. With advantages that include simplicity, low cost, flexibility, portability, and high sensitivity, the proposed optical device will be potentially useful for on-site chemical analysis measurements.

DOI： 10.1063/1.5118812

Language：Japanese  

電気関係学会九州支部連合大会講演論文集

Language：Japanese  

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.7567/1347-4065/ab1e3c

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OE.27.019615

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OE.27.019615

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.23919/CLEO.2019.8749640

Language：Others   Publishing type：Research paper (other academic)  

© 2019 The Author(s) 2019 OSA. 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.

DOI： 10.23919/CLEO.2019.8749640

Language：English   Publishing type：Research paper (other academic)  

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.

Language：English   Publishing type：Research paper (other academic)  

Silicone Optical Technology: Quasi Spatial Filter and its Application for Multichannel Absorption Analysis
© 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.

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.5054824

Language：English  

Language：English  

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

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 <jrn>[J. Am. Ceram. Soc. 86(3), 480-486 (2003)]</jrn> in the soft diffusion model can explain the CaF2 : PDMS compound film transmittance spectrum in the UV region, and the bandwidth narrowing condition. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

DOI： 10.1364/OME.9.001002

Language：Others   Publishing type：Research paper (scientific journal)  

© 2019 Optical Society of America. 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.

DOI： 10.1364/OME.9.001002

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OME.9.001150

Language：Others   Publishing type：Research paper (scientific journal)  

© 2019 Optical Society of America. 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.

DOI： 10.1364/OME.9.001150

Language：English   Publishing type：Research paper (scientific journal)  

Continuous cell culture monitoring using a compact microplate reader with a silicone optical technology-based spatial filter
Continuous cell monitoring is very important for the maintenance and control of cell multiplication and differentiation. This paper presents a compact microplate reader that is able to continuously measure a 24-well microplate (6 × 4 wells) using the optical absorption measurement method. The 24-channel plate reader consisted of a spatial filter, light emitting diode light source, and color sensors and was similarly sized with the cell culture microwell plates. A spatial filter was previously fabricated by our group using silicone optical technology (SOT). This SOT-based spatial filter has an excellent noise reduction effect. Light reflection at the optical path interface can be absorbed and only forward light can be transmitted; accordingly, a larger S/N ratio than that of conventional optical systems is expected. The fabricated 24-channel plate reader permits real-time cell monitoring during cultivation on the clean bench and in cell culture conditions by incorporating the SOT spatial filter. Using the device, it was possible to continuously evaluate the concentration and pH of reagents in the 24 wells in real time. Moreover, cell activity and protein production were detectable using the device. These results suggest that the newly fabricated device is a promising tool for the evaluation of cell behaviors for cell management.

DOI： 10.1063/1.5054824

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OME.9.001002

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OME.9.001150

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OL.44.000495

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OL.44.000495

Language：Others   Publishing type：Research paper (scientific journal)  

© 2019 Optical Society of America 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.

DOI： 10.1364/OL.44.000495

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OL.44.000495

Language：English  

DOI： 10.13005/ojc/350105

Other Link： http://dx.doi.org/10.13005/ojc/350105

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OE.27.019615

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.7567/1347-4065/ab1e3c

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1364/CLEO_SI.2019.SM2O.5

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1117/12.2508677

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.13005/350105

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1109/ECOC.2018.8535487

Language：Others   Publishing type：Research paper (other academic)  

© 2018 IEEE. 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.

DOI： 10.1109/ECOC.2018.8535487

Language：English   Publishing type：Research paper (other academic)  

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.

Language：Others   Publishing type：Research paper (other academic)  

© 2018 OSA. 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.

Language：Others   Publishing type：Research paper (other academic)  

© 2018 OSA. 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.

Language：Others   Publishing type：Research paper (other academic)  

© 2018 OSA. 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.

Language：English   Publishing type：Research paper (other academic)  

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.

Language：English   Publishing type：Research paper (other academic)  

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.

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OE.26.005800

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OE.26.007140

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OE.26.005800

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OE.26.007140

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OE.26.000233

Language：Japanese  

Fabrication and Lasing Evaluation of Fluorinated Spherical Polymer based Microdisk Cavity Printed by Ink-Jet Technique

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OE.26.000233

Language：English   Publishing type：Research paper (other academic)  

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.

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1364/CLEO_SI.2018.STh1I.7

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1364/CLEO_AT.2018.JTh2A.86

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1364/CLEO_AT.2018.JTh2A.81

Language：English   Publishing type：Research paper (scientific journal)  

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).

DOI： 10.1364/AO.56.009900

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/AO.56.009900

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1364/CLEO_SI.2017.JTu5A.119

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1063/1.4986825

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1063/1.4986825

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1021/acsami.7b05570

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1038/s41598-017-08708-1

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1021/acsami.7b05570

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1038/s41598-017-08708-1

Language：Japanese  

昨今の物作り・流通はコンピュータとインターネットの影響により大きくその形態が変化しており，情報産業を皮切りにあらゆる業種で変革がみられる。本稿では「プリンタブル」を光技術と関連づける上で，まず「プリント」の概念をソフトウエア・ハードウエアの概念から再定することを試み，その結果に沿った著者の最近の研究を２例報告する。

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/j.talanta.2015.11.066

Language：English   Publishing type：Research paper (other academic)  

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.

DOI： 10.1364/CLEO_AT.2017.JTu5A.119

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/j.talanta.2015.11.066

Language：English   Publishing type：Research paper (other academic)  

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 4^th 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.

DOI： 10.1364/LIC.2017.LWA5.10

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OME.6.003417

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： OME.6.003045

Other Link： https://www.osapublishing.org/DirectPDFAccess/A7DB111A-0B89-F4E1-ABE7A985EC33DEC9_349770/ome-6-10-3045.pdf

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OME.6.003045

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： OME.6.003417

Other Link： https://www.osapublishing.org/ome/abstract.cfm?uri=ome-6-11-3417

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1063/1.4954163

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1063/1.4954163

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1093/jmicro/dfv015

Language：English  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1038/srep10623

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English  

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.

DOI： 10.1364/LIC.2015.T4A.5

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/j.nut.2014.08.008

Language：English  

DOI： 10.1117/12.2078965

Language：Others   Publishing type：Research paper (other academic)  

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/j.dyepig.2013.03.013

Language：English   Publishing type：Research paper (international conference proceedings)  

Other Link： http://www.opticsinfobase.org/abstract.cfm?URI=OECC_PS-2013-WS3_3

Language：English  

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.

Language：English   Publishing type：Research paper (international conference proceedings)  

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.

DOI： 10.1364/CLEO_SI.2013.CF1I.5

Other Link： http://www.opticsinfobase.org/abstract.cfm?URI=CLEO_SI-2013-CF1I.5

Language：English  

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.

Language：English  

Language：Others   Publishing type：Research paper (scientific journal)  

Disposable and miniaturized organic photodiodes with spectral-resolving capabilities are fabricated based on polymeric conductive films doped with cyanine dyes by a drop-on-demand (DoD) inkjet method. The sensitivity and spectral resolution of the photodiodes at the J-aggregate absorption peaks of the corresponding cyanine dyes are improved by at least 800 times after the sequential in situ stacking of inkjet printed functional layers and optimization of the architecture, including the layer thickness and J-aggregate formation. The photodiodes are integratable onto the flowcytometry chips with waveguide laser arrays, demonstrating a spectral-resolving capability of ∼0.1 nm. © The Royal Society of Chemistry.

DOI： 10.1039/c2tc00743f

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OME.3.000176

Language：Japanese  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：Japanese  

Development of Integratable Laser for Optofluidic Chip

Language：Japanese  

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.

DOI： 10.2530/jslsm.33.142

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OE.20.014938

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OE.20.004690

Language：English   Publishing type：Research paper (other academic)  

Language：Japanese   Publishing type：Research paper (other academic)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

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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.

DOI： 10.1016/j.optmat.2010.12.011

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/j.orgel.2010.11.011

Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1364/OE.18.022080

Language：Japanese  

Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese  

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Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

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

DOI： 10.1143/JJAP.48.112503

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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

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Language：Japanese  

Primitive Integration of Waveguide DFB Dye lasers and Electrophoresis Chip

Language：Japanese  

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

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Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

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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.

DOI： 10.1080/15421400601027908

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1080/15421400601027684

Language：Japanese  

Language：Japanese  

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/OL.31.001492

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1109/JQE.2006.871557

Language：Japanese  

Trial on integration of conversion-efficiency-modulation on periodically-poled SHG device

Language：Japanese  

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.

DOI： 10.15017/1516858

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10043-005-0301-x

Language：English   Publishing type：Research paper (scientific journal)  

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.

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.1904717

Language：Others  

Waveguide dye laser including a SiO2 nanoparticle-dispersed random scattering active layer

DOI： 10.1063/1.1904717

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1143/JJAP.44.1759

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1143/JJAP.44.1759

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/15421400490505875

Language：Japanese  

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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&#37; and the threshold energy of 0.34μJ were achieved, respectively.

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/JQE.2003.810272

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1109/JQE.2003.810272

Language：English   Publishing type：Research paper (scientific journal)  

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.

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1143/JJAP.41.6370

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/AO.41.005030

Language：English   Publishing type：Research paper (scientific journal)  

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 (<0.1 nm) was obtained. A scheme for digital spectroscopy is also proposed based on this laser array, and absorption spectroscopy of sodium atoms without wavelength scanning is demonstrated by use of a sodium-vapor cell. (C) 2002 Optical Society of America.

DOI： 10.1364/OL.27.001220

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1364/AO.41.002328

Language：English   Publishing type：Research paper (scientific journal)  

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.

Language：English   Publishing type：Research paper (scientific journal)  

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.

Language：English   Publishing type：Research paper (scientific journal)  

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.

Language：English   Publishing type：Research paper (scientific journal)  

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%.

DOI： 10.1246/bcsj.72.1197

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1143/jjap.37.6403

Language：English  

Language：English  

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10043-998-0242-2

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1063/1.120215

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/S0030-4018(96)00465-8

Language：English   Publishing type：Research paper (scientific journal)  

Operation of Rhodamine 6G Dye Laser in Water Solution
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.

DOI： 10.1143/JJAP.34.3093

Language：Japanese  

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.

DOI： 10.5111/bunkou.44.10

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/0030-4018(94)90179-1

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1016/0030-4018(94)90429-4

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1021/ac00063a028

Language：English   Publishing type：Research paper (scientific journal)  

Application of a Selective Laser Ionization Photodetector for Detection of Raman Scattering in Flames

Language：English   Publishing type：Research paper (scientific journal)  

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.

DOI： 10.1021/ac00206a006

Language：Japanese   Book type：Scholarly book

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：徳島大学   Country：Japan  

Event date： 2023.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2023.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2023.11

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Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2023.9

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Venue：熊本城ホール   Country：Japan  

Event date： 2023.9

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Venue：熊本城ホール   Country：Japan  

Event date： 2023.9

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Event date： 2023.6

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Venue：Munich   Country：Germany  

Event date： 2023.6

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Country：Japan  

Event date： 2023.6

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Venue：Munich   Country：Germany  

Event date： 2023.6

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Venue：Munich   Country：Germany  

Event date： 2022.11

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Event date： 2022.11

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Event date： 2022.9

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Grating Integrated Si3N4 Microring Laser Based on Active Cladding by Dye-Doped Polymer: Discussion on Stopband and Free Spectral Range

Event date： 2022.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Pacifico Yokohama   Country：Japan  

Event date： 2022.1

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2021.12

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Country：Other  

Event date： 2021.12

Language：English  

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Surface charge control of microdisk lasers for minimizing the non-specific adsorption of biomolecules

Event date： 2021.12

Language：Japanese  

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Event date： 2021.12

Language：Japanese  

Country：Other  

Event date： 2021.12

Language：Japanese  

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Event date： 2021.12 - 2023.12

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Event date： 2021.12

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Event date： 2021.12

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Event date： 2021.1

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：オンライン   Country：Other  

Event date： 2021.1

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Other  

Event date： 2021.1

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Venue：オンライン   Country：Other  

Event date： 2021.1

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Venue：オンライン   Country：Other  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Other  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Other  

Event date： 2020.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Online   Country：Other  

Event date： 2020.8

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Country：Other  

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.

Event date： 2020.8

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.

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Event date： 2020.5

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Country：Other  

Fluorinated hyper branched polymer based active microdisk was fabricated by ink-jet printing method. The carboxyl functional group of the polymer was used for the biotinylation of microdisk and then adsorption characteristics of avidin were evaluated.

Event date： 2020.3

Language：English   Presentation type：Oral presentation (general)  

Venue：McCormick Place Convention Center, Chicago IL   Country：United States  

Event date： 2020.3

Language：English   Presentation type：Oral presentation (general)  

Venue：McCormick Place Convention Center, Chicago IL   Country：United States  

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.

Event date： 2020.3

Language：English   Presentation type：Oral presentation (general)  

Venue：McCormick Place Convention Center, Chicago IL   Country：United States  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Kagoshima   Country：Japan  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Kagoshima   Country：Japan  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Kagoshima   Country：Japan  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：筑波山温泉   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本大学工学部 黒髪南地区   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本大学工学部 黒髪南地区   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本大学工学部 黒髪南地区   Country：Japan  

2
九大シ情 ○

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州工業大学 戸畑キャンパス   Country：Japan  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州工業大学 戸畑キャンパス   Country：Japan  

電気関係学会九州支部連合大会講演論文集