Dr. Yoshiharu Kei Urata Profile

Dr. Yoshiharu Kei Urata

President/CEO at PHLUXi Inc

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Publications (17)

Proceedings Article | 13 March 2023 Presentation

Terahertz wave parametric wavelength conversion monitored by spectral drill cavity

Shin'ichiro Hayashi, Seigo Ohno, Katsuhiko Miyamoto, Yoshiharu Urata, Norihiko Sekine

Proceedings Volume PC12420, PC1242007 (2023) https://doi.org/10.1117/12.2650843

KEYWORDS: Terahertz radiation, Nonlinear crystals, Nd:YAG lasers, Pyroelectric detectors, Standards development, Spatial light modulators, Physics, Phase shifts, Output couplers, Mirrors

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Proceedings Article | 7 March 2022 Poster + Presentation

Frequency controlled terahertz wave parametric generation based on spectral drill cavity

Shin'ichiro Hayashi, Yoshiharu Urata, Seigo Ohno, Katsuhiko Miyamoto, Norihiko Sekine

Proceedings Volume PC12000, PC120000M (2022) https://doi.org/10.1117/12.2607441

KEYWORDS: Terahertz radiation, Nonlinear crystals, Resonators, Nd:YAG lasers, Pyroelectric detectors, Standards development, Spatial light modulators, Physics, Phase shifts, Output couplers

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Proceedings Article | 1 March 2019 Presentation + Paper

Multimilliwatt pulsed terahertz-wave source pumped by dual fiber lasers for imaging application

Yoshio Wada, Takumi Satoh, Yasuhiro Higashi, Yoshiharu Urata

Proceedings Volume 10917, 109170W (2019) https://doi.org/10.1117/12.2509324

KEYWORDS: Terahertz radiation, Fiber lasers, Medicine, Crystals, Imaging spectroscopy, Photography, Spectroscopy, Nonlinear crystals, Image transmission

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Proceedings Article | 23 February 2018 Presentation + Paper

High-repetition-rate tunable narrowband terahertz-wave generation based on nonlinear frequency conversion pumped by dual fiber lasers in MgO:LiNbO3

Yoshio Wada, Takumi Satoh, Yasuhiro Higashi, Yoshiharu Urata

Proceedings Volume 10531, 1053107 (2018) https://doi.org/10.1117/12.2287293

KEYWORDS: Terahertz radiation, Fiber lasers, Crystals, Laser crystals, Pulsed fiber lasers, Imaging spectroscopy, Head, Nonlinear crystals, Fiber amplifiers, Absorption

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Proceedings Article | 17 February 2010 Paper

Highly reliable 198-nm light source for semiconductor inspection based on dual fiber lasers

Shinichi Imai, Kazuto Matsuki, Nobutaka Kikuiri, Katsuhiko Takayama, Osamu Iwase, Yoshiharu Urata, Tatsuya Shinozaki, Yoshio Wada, Satoshi Wada

Proceedings Volume 7580, 75800H (2010) https://doi.org/10.1117/12.840467

KEYWORDS: Light sources, Inspection, Fiber lasers, Fiber amplifiers, Photomasks, Optical amplifiers, Semiconductors, Pulsed laser operation, Oscillators

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Proceedings Article | 9 December 2008 Paper

Q-switch operation of thulium and holmium-doped YAG ceramic laser at room temperature

Yoshiharu Urata, Masaki Yumoto, Oleg Louchev, Satoshi Wada

Proceedings Volume 7153, 715315 (2008) https://doi.org/10.1117/12.804774

KEYWORDS: Q switching, Ceramics, YAG lasers, Pulsed laser operation, Q switched lasers, Holmium, Rod lasers, Thulium, Ions, Crystals

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Proceedings Article | 20 November 2008 Paper

Comparison of tunable lasers based on diode pumped Tm-doped crystals

Jan Šulc, Helena Jelínková, Petr Koranda, Pavel Černý, Jan Jabczyński, Waldemar Żendzian, Jacek Kwiatkowski, Yoshiharu Urata, Mikio Higuchi

Proceedings Volume 7141, 71410C (2008) https://doi.org/10.1117/12.822357

KEYWORDS: Crystals, Laser crystals, Semiconductor lasers, Diodes, Tunable lasers, Absorption, Laser resonators, Resonators, Reflectivity, Output couplers

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We report on continuously tunable operation of a diode pumped lasers based on Tm-doped materials, emitting in the 1.8 - 2.μ1 m spectral band. In our study we compare results obtained with three various single crystals doped by Tm³⁺ ions: Yttrium Aluminum perovskite YAP (YAlO₃), Gadolinium orthovanadate GdVO₄, and Yttrium Lithium Fluoride YLF (YLiF₄). Following samples were available: the 3mm long a-cut crystal rod of Tm:YAP with 4% at. Tm/Y (diameter 3 mm); the 8mm long b-cut crystal rod of Tm:YLF with 3.5% at. Tm/Y (diameter 3 mm); the 2.7mm long a-cut crystal block of Tm:GdVO₄ with 2% at. Tm/Gd (crystal face 5×3 mm). For active medium pumping, the laser diode radiation was used. Because the tested samples differs significantly in absorption spectra, two fibre-coupled (core diameter 400 µm) temperature-tuned laser diodes were used: first operating at wavelength 793nm was used for Tm:YAP and Tm:YLF; the second operating at wavelength 802nm was used for Tm:GdVO₄. In both cases, the continuous power up to 20W was available for pumping. The diode radiation was focused into the active crystal by two achromatic doublet lenses with the focal length f = 75 mm. The measured radius of pumping beam focus inside the crystal was 260 µm. The longitudinally diode pumped crystals were tested in linear, 80mm long, hemispherical laser cavity. The curved (radius 150mm) output coupler reflectivity was ~ 97 % in range from 1.8 up to 2.1 μm. The pumping flat mirror had maximal reflectivity in this range and it had high transmission around 0.8 μm. A 1.5mm thick birefringent plate made from quartz (Lyot filter) inserted under a Brewster's angle was used as a tuning element. This plate was placed inside the resonator between the crystal and the output coupler. Using Tm:YAP crystal, the maximal output power of 2.8W in this set-up was obtained. The laser could be tuned from 1865nm up to 2036nm with a maximum at 1985 nm. Laser based on Tm:YLF crystal was tunable from 1835nm up to 2010nm with a maximum at 1928 nm (3.0W was reached). Using the Tm:GdVO₄ tunable operation with greater that 1W output at 1920nm and 130nm tuning range (1842-1972 nm) was demonstrated. The overall reached tuning range of over 200nm covers many important atmospheric absorption lines and contains also the local absorption peak of liquid water, making them attractive for applications such as high resolution spectroscopy, atmospheric remote sensing, laser radar, and laser microsurgery.

Proceedings Article | 22 April 2008 Paper

Tm-doped vanadates under pulsed pumping with variable duty-cycle: impact on lasing and fluorescence

Jan Šulc, Pavel Černý, Helena Jelínková, Witold Ryba-Romanowski, Radoslaw Lisiecki, Piotr Solarz, Grazina Dominiak-Dzik, Yoshiharu Urata, Mikio Higuchi

Proceedings Volume 6998, 69980T (2008) https://doi.org/10.1117/12.779298

KEYWORDS: Crystals, Upconversion, Semiconductor lasers, Laser crystals, Luminescence, Diodes, Temperature metrology, Continuous wave operation, Thulium

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Proceedings Article | 13 March 2008 Paper

Tunable lasers based on diode pumped Tm-doped vanadates Tm:YVO4, Tm:GdVO4, and Tm:LuVO4

Jan Šulc, Petr Koranda, Pavel Černý, Helena Jelínková, Yoshiharu Urata, Mikio Higuchi, Witold Ryba-Romanowski, Radosław Lisiecki, Piotr Solarz, Grażina Dominiak-Dzik, Marcin Sobczyk

Proceedings Volume 6871, 68711V (2008) https://doi.org/10.1117/12.763011

KEYWORDS: Crystals, Tunable lasers, Diodes, Semiconductor lasers, Laser resonators, Absorption, Resonators, Laser crystals, Continuous wave operation, Thulium

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Proceedings Article | 9 August 2007 Paper

Coupled thermo-optical modeling of high-power operation of Tm, Ho:YLF solid-state lasers

Oleg Louchev, Yoshiharu Urata, Norihito Saito, Satoshi Wada

Proceedings Volume 6731, 67310D (2007) https://doi.org/10.1117/12.751893

KEYWORDS: Crystals, Holmium, Thulium, Q switching, Absorption, Chromium, Solid state lasers, Laser crystals, Pulsed laser operation, Thermal effects

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Proceedings Article | 22 December 2006 Paper

Characterization of thulium- and holmium-doped YAG ceramic laser materials

Yoshiharu Urata, Toshimasa Kozeki, Akihito Kudo, Atsushi Sato, Kazuhiro Asai, Satoshi Wada

Proceedings Volume 6409, 64091J (2006) https://doi.org/10.1117/12.697908

KEYWORDS: Ceramics, Crystals, YAG lasers, Thulium, Diodes, Holmium, Absorption, Ions, Semiconductor lasers, Pulsed laser operation

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Proceedings Article | 22 February 2006 Paper

Continuous-wave visible laser by intracavity-doubled fiber laser

Tatsuya Shinozaki, Yushi Kaneda, Yoshiharu Urata, Satoshi Wada

Proceedings Volume 6100, 610003 (2006) https://doi.org/10.1117/12.649522

KEYWORDS: Fiber lasers, Fiber Bragg gratings, Mirrors, Laser resonators, Semiconductor lasers, Resonators, Continuous wave operation, Second-harmonic generation, Reflectors, Ytterbium

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Proceedings Article | 12 January 2005 Paper

Diode-pumped CW Tm:GdVO4 laser using floating zone-grown crystals

Yoshiharu Urata, Hiroshi Machida, Mikio Higuchi, Kohei Kodaira, Satoshi Wada

Proceedings Volume 5653, (2005) https://doi.org/10.1117/12.578230

KEYWORDS: Crystals, Absorption, Laser crystals, Thulium, Semiconductor lasers, Luminescence, Continuous wave operation, Fabry–Perot interferometers, Neodymium, Ions

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Proceedings Article | 12 January 2005 Paper

Normal-mode and Q-switched operations of a conductively cooled Tm,Ho:LLF laser with a triangular-prism rod

Atsushi Sato, Kazuhiro Asai, Hiroshi Machida, Yoshiharu Urata, Satoshi Wada, Kohei Mizutani, Toshikazu Itabe

Proceedings Volume 5653, (2005) https://doi.org/10.1117/12.578189

KEYWORDS: Rod lasers, Q switched lasers, Waveguides, Q switching, Polishing, Surface finishing, Pulsed laser operation, Mirrors, Reflection, Resonators

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Proceedings Article | 23 December 2003 Paper

CW Tm:GdVO4 laser pumped by 808-nm laser diodes operated at room temperature

Yoshiharu Urata, Satoshi Wada

Proceedings Volume 5154, (2003) https://doi.org/10.1117/12.504527

KEYWORDS: Crystals, Absorption, Thulium, Semiconductor lasers, Ions, Luminescence, Laser crystals, Continuous wave operation, YAG lasers, Polarization

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Proceedings Article | 21 March 2003 Paper

Thulium-doped gadolinium vanadate single crystals for efficient 2-um source of practical use

Yoshiharu Urata, Hiroshi Machida, Mikio Higuchi, Kohei Kodaira, Satoshi Wada

Proceedings Volume 4893, (2003) https://doi.org/10.1117/12.466453

KEYWORDS: Crystals, Absorption, Thulium, Gadolinium, Luminescence, Polarization, Laser crystals, Light sources, Semiconductor lasers, Neodymium

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Proceedings Article | 9 September 1999 Paper

DFG THz-wave generation in DAST using dual-wavelength Ti:Al2O3 laser

Maya Mizuno, Kodo Kawase, Syunichi Soma, Hidenori Takahashi, Yoshiharu Urata, Satoshi Wada, Hideo Tashiro, Hiromasa Ito

Proceedings Volume 3828, (1999) https://doi.org/10.1117/12.361025

KEYWORDS: Crystals, Sapphire lasers, Nonlinear crystals, Laser crystals, Terahertz radiation, Polarization, Pulsed laser operation, Fabry–Perot interferometers, Difference frequency generation, Diodes

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Showing 5 of 17 publications

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