Updated on 2023/03/31

写真a

 
KITAJIMA Shotaro
 
Organization
Graduate School of Engineering Electronics 3 Assistant Professor
Graduate School
Graduate School of Engineering
Undergraduate School
School of Engineering Electrical Engineering, Electronics, and Information Engineering
Title
Assistant Professor
External link

Degree 1

  1. 博士（工学） （ 2019.3   電気通信大学 ） 

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Research Interests 5

  1. モード同期レーザー

  2. 固体レーザー

  3. 薄ディスクレーザー

  4. 超短パルスレーザー

  5. ファイバーレーザー

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Research Areas 1

  1. Nanotechnology/Materials / Optical engineering and photon science

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Research History 2

  1. Nagoya University   Graduate School of Engineering Electronics   Assistant Professor

    2021.10

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    Country：Japan

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  2. Osaka University   Institute of Laser Engineering   Designated assistant professor

    2019.4 - 2021.9

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Education 2

  1. The University of Electro-Communications

    2014.4 - 2019.3

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  2. Nagano National College of Technology

    2007.4 - 2012.3

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Professional Memberships 2

  1. 日本レーザー学会

    2014

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  2. Optica

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Committee Memberships 2

  1. 一般社団法人レーザー学会学術講演会第43回年次大会   総務係委員  

    2022.1 - 2023.1   

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    Committee type：Academic society

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  2. レーザー学会中部支部   庶務幹事  

    2021.10   

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    Committee type：Academic society

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Awards 6

  1. レーザー学会次世代FL研究会，優秀口頭発表賞

    2022.11   レーザー学会  

    北島将太朗

  2. 第41回学術講演会年次大会 優秀論文発表賞

    2021.1   一般社団法人レーザー学会   インククラッドにて寄生発振を抑制した1 J/100 Hz低温冷却Yb:YAGレーザー増幅器

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  3. “Outstanding Oral Runner-up Presentation Award”, Advanced Solid-State Lasers (ASSL2018)

    2018.11   OSA   Sub-100 fs Kerr-Lens Mode-Locked Thin-Disk Lasers Based on Ceramic Gain Media

    Shotaro Kitajima

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  4. “The Best Student Poster Paper Award,” The 7th Advanced Lasers and Photon Sources

    2018.4   177 fs Pulses From Kerr-Lens Mode-Locked Yb:Lu2O3 Ceramic Thin Disk Laser

    Shotaro Kitajima

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  5. “The Best Student Oral Paper Award,” The 4th Advanced Lasers and Photon Sources

    2015.4   Kerr-lens mode-locked Yb3+ -doped Lu3Al5O12 ceramic laser

    Shotaro Kitajima

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  6. 第15回レーザー学会東京支部研究会 ポスター講演 特別賞

    2015.3   レーザー学会東京支部   高出力Kerrレンズモード同期Yb3+添加Lu3Al5O12セラミックレーザー

    北島将太朗

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Papers 18

  1. Controllable, intense spectral peaking with a spectral filter and optical fiber

    Norihiko Nishizawa, Sakiko Kobata, Shotaro Kitajima

    Optics Letters   Vol. 47 ( 23 ) page： 6165 - 6168   2022.12

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1364/OL.471957

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  2. Spectral peaking in an ultrashort-pulse fiber laser oscillator with a molecular gas cell

    Norihiko Nishizawa, Shotaro Kitajima, Youichi Sakakibara

    Optics Letters   Vol. 47 ( 10 ) page： 2422 - 2425   2022.5

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

    Here we report the demonstration of a spectral peaking phenomenon in a fiber laser oscillator. An HCN gas cell was inserted in an ultrashort-pulse Er-doped fiber laser with single-wall carbon nanotubes. Sech(2)-shaped ultrashort pulses with intense multiple sharp spectral peaks were stably generated. When the generated pulses were coupled into highly nonlinear fiber, enhanced multiple spectral peaks were generated by periodical spectral peaking in the optical fiber. The characteristics and physical mechanism of spectral peaking in the fiber laser were investigated via numerical simulations. As the magnitude of absorption was increased, the magnitude of the generated spectral peaks increased almost exponentially. It was clarified that the spectral peaks were generated through the accumulation of filtering components generated in each round trip. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

    DOI： 10.1364/OL.458643

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  3. 10-J, 100-Hz conduction-cooled active-mirror laser

    Jumpei Ogino, Shigeki Tokita, Shotaro Kitajima, Hidetsugu Yoshida, Zhaoyang Li, Shinji Motokoshi, Noboru Morio, K. O. J. I. TSUBAKIMOTO, Kana Fujioka, Ryosuke Kodama, Junji Kawanaka

    OPTICS CONTINUUM   Vol. 1 ( 5 ) page： 1270 - 1277   2022.5

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

    High average power lasers with a high pulse energy are of considerable interest in various fields such as high-energy-density physics. Light-absorbing edge cladding is effective in suppressing parasitic oscillations in high-pulse-energy disk lasers; however, the large amount of heat generated from the cladding can affect the laser medium. We develop an improved conduction-cooled active-mirror laser with a double-sided cooled-edge cladding. A stable laser output with a pulse energy of 10 J at a repetition rate of 100 Hz was achieved using six liquid-nitrogen-cooled active-mirrors in the main amplifier. This study shows that aggressive cooling of the edge cladding is highly effective in decreasing the temperature rise and controlling the temperature distribution in the laser medium.

    DOI： 10.1364/OPTCON.456554

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  4. Kerr-lens mode-locked Yb:LuAG ceramic thin-disk laser Reviewed

    Shotaro Kitajima, Akira Shirakawa, Hideki Yagi, Takagimi Yanagitani

    Optics Letters   Vol. 46 ( 10 ) page： 2312 - 2315   2021.5

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

    DOI： 10.1364/OL.423865

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  5. Dispersion-Managed Tm-Ho Co-Doped Ultrashort Pulse Fiber Laser Using Single-Walled Carbon Nanotube and Spectral Filter

    Fukazawa Keisuke, Zhou Ying, Kitajima Shotaro, Saito Takeshi, Sakakibara Youichi, Nishizawa Norihiko

    APPLIED SCIENCES-BASEL   Vol. 12 ( 23 )   2022.12

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    Publisher：Applied Sciences (Switzerland)  

    Featured Application: Biomedical imaging, Environmental spectroscopy, LIDAR, Medicine, and Laser processing. In this paper, we have demonstrated a dispersion-managed, high-power, Tm-Ho co-doped ultrashort pulse fiber laser using a single walled carbon nanotube (SWNT) dispersed in polyimide film. An in-line type spectral filter was developed to control the output pulse spectra. Two SWNT films with different modulation depths were examined as a mode-locker. Normal dispersion fiber was used in the fiber laser oscillator, and dependence on net cavity dispersion was investigated. Passive mode-locking was achieved in a wide dispersion range, from −0.319 to +0.101 ps2. Stable soliton mode-locking operation and dissipative soliton mode-locking operations were observed. The pumping efficiency was ~3 times higher than that in a Tm-doped fiber laser with a similar configuration. The developed fiber laser showed self-start and stable operations, and this laser is useful for practical applications.

    DOI： 10.3390/app122312369

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  6. Spectral Peaking in Ultrashort Pulse Fiber Lasers with Molecular Gas Cell

    Nishizawa N., Kitajima S., Sakakibara Y.

    2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings     2022

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    Publisher：2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings  

    We demonstrated spectral peaking phenomenon in fiber laser cavity for the first time. Ultrashort soliton pulse with multiple sharp spectral peaks were successfully generated in Er-doped SWNT fiber laser with HCN gas cell.

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  7. Spectral Peaking in Ultrashort Pulse Fiber Lasers with Molecular Gas Cell

    Nishizawa N., Kitajima S., Sakakibara Y.

    Optics InfoBase Conference Papers     2022

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    Publisher：Optics InfoBase Conference Papers  

    We demonstrated spectral peaking phenomenon in fiber laser cavity for the first time. Ultrashort soliton pulse with multiple sharp spectral peaks were successfully generated in Er-doped SWNT fiber laser with HCN gas cell.

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  8. Speckle Reduction by Frequency Compounding in 1.7 μm Optical Coherence Tomography using Tunable QuasiSupercontinuum Laser Source

    Chen Y., Yamanaka M., Kitajima S., Nishizawa N.

    2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings     2022

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    Publisher：2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings  

    Speckles in OCT hinder visibility of finescale structures. We demonstrated speckle reduced OCT imaging using 1.7 μm tunable Quasisupercontinuum fiber laser source, and the improvement of image contrast in deep tissue imaging was successfully confirmed.

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  9. Speckle Reduction by Frequency Compounding in 1.7 μm Optical Coherence Tomography using Tunable Quasi-Supercontinuum Laser Source

    Chen Y., Yamanaka M., Kitajima S., Nishizawa N.

    Optics InfoBase Conference Papers     2022

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    Publisher：Optics InfoBase Conference Papers  

    Speckles in OCT hinder visibility of fine-scale structures. We demonstrated speckle reduced OCT imaging using 1.7 μm tunable Quasi-supercontinuum fiber laser source, and the improvement of image contrast in deep tissue imaging was successfully confirmed.

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  10. 10 J operation of a conductive-cooled Yb:YAG active-mirror amplifier and prospects for 100 Hz operation Reviewed

    Jumpei Ogino, Shigeki Tokita, Shotaro Kitajima, Hidetsugu Yoshida, Zhaoyang Li, Shinji Motokoshi, Noboru Morio, Koji Tsubakimoto, Kana Fujioka, Ryosuke Kodama, Junji Kawanaka

    OPTICS LETTERS   Vol. 46 ( 3 ) page： 621 - 624   2021.2

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：OPTICAL SOC AMER  

    We report, to the best of our knowledge, the highest power conductive-cooled active-mirror amplifier (CcAMA) using Yb:YAG with a pulse energy of 10 J. By using four liquid-nitrogen circulating cooled laser heads, we achieved a repetition rate, pulse energy, and average power of 33.3 Hz, 9.3 J, and 310 W, respectively. The problem of wavefront distortion, which is difficult to solve with a large-aperture active-mirror laser, is suppressed by using reinforcing materials with the same thermal expansion coefficient. We have confirmed that the wavefront distortion is small (0.15 lambda P-V per head) at 100 Hz operation, which paves the way for 100 Hz operation with the CcAMA concept. (C) 2021 Optical Society of America

    DOI： 10.1364/OL.414926

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  11. 1 J/100 Hz cryogenically-cooled Yb:YAG laser amplifier with ink-cladding for the suppression of parasitic lasing

    Kitajima S., Ogino J., Tokita S., Zhaoyang L., Motokoshi S., Morio N., Tsubakimoto K., Yoshida H., Fujioka K., Ueda K.I., Kodama R., Kawanaka J.

    Optics InfoBase Conference Papers     2021

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    Publisher：Optics InfoBase Conference Papers  

    A stable operation of 1.1 J/100 Hz 10 ns laser pulses were achieved from a single cryogenically cooled Yb:YAG rod amplifier with ink-cladding. The efficiency and gain coefficient were 44% and 383, respectively.

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  12. Toward 10J, 100Hz active-mirror amplifier

    Ogino J., Tokita S., Kitajima S., Yoshida H., Li Z., Motokoshi S., Morio N., Tsubakimoto K., Fujioka K., Kodama R., Kawanaka J.

    Optics InfoBase Conference Papers     2020.10

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    Language：English   Publisher：Optics InfoBase Conference Papers  

    We have developed a conductive-cooled Yb:YAG active-mirror amplifier with an diameter of 50 mm and a liquid-nitrogen circulation system. The high thermal capability that enables 10 J, 50 Hz laser amplification was demonstrated successfully.

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  13. Sub-100 fs pulses generation from Kerr-lens mode-locked Yb: Lu2O3 ceramic thin-disk laser Reviewed

    Shotaro Kitajima, Akira Shirakawa, Hideki Yagi, Takagimi Yanagiani

    Optics Letters   Vol. 43 ( 21 ) page： 5451 - 5454   2018.10

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1364/OL.43.005451

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  14. Kerr-lens mode-locked Yb:Lu2O3 ceramic thin-disk laser Reviewed

    Shotaro Kitajima, Akira Shirakawa, Hideki Yagi, Takagimi Yanagitani

    Optics InfoBase Conference Papers   Vol. 2018   2018

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    Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：OSA - The Optical Society  

    The first Kerr-lens mode-locked Yb:Lu2O3 ceramic thin-disk laser was demonstrated. The shortest pulse duration was 177 fs with 3.2 W output power. The output power of 17 W with 588 fs pulses was also demonstrated.

    DOI： 10.1364/CLEO_SI.2018.SF2N.5

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  15. Yb3+-doped CaF2-LaF3 ceramics laser Reviewed

    Shotaro Kitajima, Kentaro Yamakado, Akira Shirakawa, Ken-ichi Ueda, Yoshinobu Ezura, Hitoshi Ishizawa

    OPTICS LETTERS   Vol. 42 ( 9 ) page： 1724 - 1727   2017.5

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：OPTICAL SOC AMER  

    Highly transparent ceramic is an attractive gain medium for high-power lasers due to its high fracture toughness, homogeneity, and size scalability. Here we report the first Yb3+-doped CaF2-LaF3 ceramics laser. Codoping of La3+ ion can reduce the formation of Yb2+ ions and enhance the laser efficiency. In the laser experiment, the maximum output power of 4.36 W and the maximum slope efficiency of 69.5% were obtained with a 3% La, 2% Yb sample and a 2% La, 1% Yb sample, respectively. Due to the combined properties of Yb: CaF2 and a ceramic laser gain medium, Yb: CaF2-LaF3 ceramic is a promising gain medium for a high-power ultrashort pulse laser and amplifier. (C) 2017 Optical Society of America

    DOI： 10.1364/OL.42.001724

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    Other Link： http://orcid.org/0000-0002-7082-6145

  16. CW performance and temperature observation of Yb: Lu2O3 ceramic thin-disk laser Reviewed

    Shotaro Kitajima, Hiroaki Nakao, Akira Shirakawa, Hideki Yagi, Takagimi Yanagitani

    Optics InfoBase Conference Papers   Vol. 2017   2017

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    Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：OSA - The Optical Society  

    CW Yb: Lu2O3 ceramic thin-disk laser with the maximum output power of 174 W was demonstrated. Slope efficiency was 54%. Disk temperature during lasing was observed and maximum temperature was 84.1 °C under 5.5 kW/cm2 pumping.

    DOI： 10.1364/ASSL.2017.JM5A.32

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  17. Kerr-lens mode-locked Yb3+-doped Lu3Al5O12 ceramic laser Reviewed

    Shotaro Kitajima, Hiroaki Nakao, Akira Shirakawa, Hideki Yagi, Takagimi Yanagitani

    OPTICS LETTERS   Vol. 41 ( 19 ) page： 4570 - 4573   2016.10

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：OPTICAL SOC AMER  

    Yb:LuAG is a promising gain medium for high-power lasers due to its high thermal conductivity and large emission cross section. Although narrowband gain media such as Yb: LuAG are not considered to be suitable for the generation of sub-100 fs pulses, we have achieved generation of 91 fs pulses with Yb: LuAG ceramic by the Kerr-lens mode-locking (KLM) technique. The obtained average power, pulse energy, and peak power were 1.64 W, 20.0 nJ, and 220 kW, respectively. These are, to the best of our knowledge, the first demonstration of KLM and the new records based on both Yb: LuAG ceramic and single crystal. (C) 2016 Optical Society of America

    DOI： 10.1364/OL.41.004570

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    Other Link： http://orcid.org/0000-0002-7082-6145

  18. Highly Efficient Yb3+-doped CaF2-LaF3 Ceramic Laser Reviewed

    Shotaro Kitajima, Yuki Higashi, Hiroaki Nakao, Akira Shirakawa, Ken-ichi Uedal, Yoshinobu Ezura, Hitoshi Ishizawa

    2016 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)     2016

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    Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

    We prepared transparent Yb:CaF2-LaF3 ceramics with different combinations of doping concentrations of Yb3+ and La3+ and obtained CW laser operation with maximum output of 3.97 W. The maximum slope efficiency was as high as 73.1%.

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MISC 1

  1. High-Power Solid-State Lasers and their Latest Trend

      Vol. 97 ( 7 ) page： 388 - 395   2021.7

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    Language：Japanese  

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Presentations 38

  1. Freely Controllable Spectral Peak Generation Using 206 MHz All-PM Fiber Laser Comb

    2023.3.15 

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    Event date： 2023.3

    Presentation type：Oral presentation (general)  

  2. 超短パルスファイバレーザーを用いたスペクトルピークの生成 Invited

    西澤典彦，北島将太朗

    レーザー学会年次大会  2023.1.18 

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    Event date： 2023.1

    Presentation type：Oral presentation (invited, special)  

  3. A 200 MHz optical frequency comb based on a Figure-9 type mode-locked laser

    2022.11.18 

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    Event date： 2022.11

    Presentation type：Oral presentation (general)  

  4. 超短パルスレーザー研究に魅せられて Invited

    北島将太朗

    次世代FL研究会  2022.11.18 

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    Event date： 2022.11

    Presentation type：Oral presentation (invited, special)  

  5. 高機能超短パルスファイバレーザー光源の開発と応用 Invited

    西澤典彦，北島将太朗

    電子情報通信学会・光ファイバ応用技術研究会（OFT）  2022.10.13 

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    Event date： 2022.10

    Presentation type：Oral presentation (invited, special)  

  6. Controllable Spectral Peak Generation with Ultrashort Pulses using LCOS-SLM Spectral Filter International conference

    Sakiko Kobata, Shotaro Kitajima, Norihiko Nishizawa

    Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR 2022)  2022.7.31 

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    Event date： 2022.7

    Presentation type：Oral presentation (general)  

  7. Characteristics of Spectral Peaking in Ultrashort Pulse Fiber Lasers with Molecular Gas Cell International conference

    Norihiko Nishizawa, Shotaro Kitajima, Youichi Sakakibara

    Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR 2022)  2022.7.31 

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    Event date： 2022.7

    Presentation type：Oral presentation (general)  

  8. Investigation on power scalability of Yb:KREW thin-disk lasers by anisotropic thermo-mechanical analysis International conference

    Shotaro Kitajima, Norihiko Nishizawa

    Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR 2022)  2022.7.31 

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    Event date： 2022.7

    Presentation type：Poster presentation  

  9. Spectral Peaking in Ultrashort Pulse Fiber Lasers With Molecular Gas Cell International conference

    Norihiko Nishizawa, Shotaro Kitajima, Youichi Sakakibara

    CLEO2022  2022.5.15 

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    Event date： 2022.5

    Presentation type：Oral presentation (general)  

  10. Speckle Reduction by Frequency Compounding in 1.7 μm Optical Coherence Tomography Using Tunable Quasi-Supercontinuum Laser Source International conference

    Ying Chen, Masahito Yamanaka, Shotaro Kitajima, and Norihiko Nishizawa

    CLEO2022  2022.5.15 

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    Event date： 2022.5

    Presentation type：Oral presentation (general)  

  11. Mechanical Speckle Noise Reduction in SD-OCT at 1.7 um Wavelength International conference

    Kensuke Yamanaka, Masahito Yamanaka, Norihiko Nishizawa

    SI-Thru2022 (Sensing and Imaging through Scattering and Fluctuating Field in Biology)  2022.4.18 

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    Event date： 2022.4

    Presentation type：Poster presentation  

  12. Spectral Control of Dispersion Managed, Highly-Efficient Tm-Ho co-doped Ultrashort Pulse Fiber Laser at 2 um Using SWNT International conference

    Keisuke Fukazawa, Ying Zhou, Shotaro Kitajima, Takeshi Saito, Yoichi Sakakibara, Norihiko Nishizawa

    The 11th Advanced Laasers and Photon Sources  2022.4.18 

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    Event date： 2022.4

    Presentation type：Oral presentation (general)  

  13. Tm-Ho Co-doped Fiber Pulse Laser for Application in Mid-infrared Pulse Generation International conference

    Jingzhe Zhang, Keisuke Fukazawa, Ying Zhou, Shotaro Kitajima, Takeshi Saito, Youichi Sakakibara, Norihiko Nishizawa

    The 11th Advanced Laasers and Photon Sources  2022.4.18 

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    Event date： 2022.4

    Presentation type：Poster presentation  

  14. Speckle reduction by spectral compounding in 1700 nm SD-OCT using tunable quasi-supercontinuum source International conference

    Ying Chen, Shotaro Kitajima, Norihiko Nishizawa

    SI-Thru2022 (Sensing and Imaging through Scattering and Fluctuating Field in Biology)  2022.4.18 

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    Event date： 2022.4

    Presentation type：Oral presentation (general)  

  15. 超短パルスファイバレーザーにおけるスペクトルピークの生成

    西澤 典彦、北島 将太朗、榊原 陽一

    第69回応用物理学会春季学術講演会  2022.3.24 

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    Event date： 2022.3

    Presentation type：Oral presentation (general)  

  16. 低温伝導冷却アクティブミラー増幅器の新規構造

    黒岩 尭彦、北島 将太朗、時田 茂樹、金井 恒人、荻野 純平、河仲 準二

    第69回応用物理学会春季学術講演会  2022.3.25 

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    Event date： 2022.3

    Presentation type：Oral presentation (general)  

  17. LCOS-SLMによるスペクトルフィルタを用いた スペクトルピークの生成と制御

    古畑 早紀子、北島 将太朗、西澤 典彦

    第69回応用物理学会春季学術講演会  2022.3.24 

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    Event date： 2022.3

    Presentation type：Oral presentation (general)  

  18. High Power Yb:KLuW Thin-Disk Laser

    2022.3.22 

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    Event date： 2022.3

    Presentation type：Oral presentation (general)  

  19. タングステン酸塩利得媒質を用いた Thin-disk レーザー

    北島 将太朗、時田 茂樹、河仲 準二

    レーザー学会学術講演会第42回年次大会  2022.1.14 

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    Event date： 2022.1

    Presentation type：Oral presentation (general)  

  20. 革新的パワーレーザーの開発 -伝導冷却アクディブミラーレーザー Invited

    荻野 純平、時田 茂樹、北島 将太朗、本越 伸二、森尾 登、椿本 孝治、吉田 英次、藤岡 加奈、植田 憲一、兒玉 了祐、河仲 準二

    レーザー学会学術講演会第42回年次大会  2022.1.14 

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    Event date： 2022.1

    Presentation type：Oral presentation (invited, special)  

  21. はんだの粘塑性を考慮した低温冷却型アクティブミラー増幅器の熱構造解析

    黒岩 尭彦、北島 将太朗、荻野 純平、時田 茂樹、河仲 準二

    レーザー学会学術講演会第42回年次大会  2022.1.14 

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    Event date： 2022.1

    Presentation type：Oral presentation (general)  

  22. 1 J/ 100 Hz cryogenically-cooled Yb:YAG laser amplifier with ink-cladding for the suppression of parasitic lasing Invited International conference

    CLEO2021  2021.5.13 

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    Event date： 2021.5

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

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  23. 1 J/100 Hz ns laser pulses generation from cryogenically-cooled Yb:YAG rod amplifier with ink-cladding International conference

    Shotaro Kitajima, Jumpei Ogino, Shigeki Tokita, Li Zhaoyang, Shinji Motokoshi, Noboru Morio, Koji Tsubakimoto, Hidetsugu Yoshida, Kana Fujioka, Ken-ichi Ueda, Ryosuke Kodama, Junji Kawanaka

    The 10th Advanced Lasers and Photon Sources (ALPS2021)  2021.4 

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    Event date： 2021.4

    Presentation type：Poster presentation  

  24. Spectral peak generation using ultrashort pulse fiber lasers Invited International conference

    N. Nishizawa, S. Kitajima, Y. Sakakibara, H. Tomida, andH. Abe

    SPIE Photoincs West  2021.1.29 

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    Event date： 2021.1

    Presentation type：Oral presentation (invited, special)  

  25. 177 fs Pulses From Kerr-Lens Mode-Locked Yb:Lu2O3 Ceramic Thin Disk Laser International conference

    Shotaro Kitajima

    The 7th Advanced Lasers and Photon Sources (ALPS)  2018.4 

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    Language：English   Presentation type：Poster presentation  

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  26. Yb:CaF2単結晶Thin-diskレーザーの開発

    小林 祐樹, 北島 将太朗, 白川 晃

    一般社団法人レーザー学会第40回年次講演会  2020.1.20 

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  27. Yb3+-doped CaF2-LaF3 Ceramic Laser International conference

    Shotaro Kitajima

    The 11th Laser Ceramics Symposium (LCS)  2015.12 

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    Language：English   Presentation type：Oral presentation (general)  

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  28. Sub-100 fs Kerr-lens mode-locked Yb3+ -doped Lu3Al5O12 ceramic laser International conference

    Shotaro Kitajima

    The 12th Laser Ceramics Symposium (LCS)  2016.12 

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    Language：English   Presentation type：Oral presentation (general)  

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  29. Sub-100 fs Kerr-lens mode-locked Yb3+ -doped Lu3Al5O12 ceramic laser International conference

    Shotaro Kitajima

    EUROPHOTON  2016.8 

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    Language：English   Presentation type：Oral presentation (general)  

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  30. Sub-100 fs Kerr-Lens Mode-Locked Thin-Disk Lasers Based on Ceramic Gain Media International conference

    Shotaro Kitajima

    ASSL  2018.11 

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    Language：English   Presentation type：Oral presentation (general)  

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  31. Mode-locked Yb3+-doped CaF2-LaF3 Ceramic Laser International conference

    Shotaro Kitajima

    CLEO/EUROPE-EQEC 2017  2017.6 

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  32. Kerr-Lens Mode-Locked Yb:Lu2O3 Ceramic Thin-Disk Laser International conference

    Shotaro Kitajima

    CLEO  2018.5 

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  33. Kerr-lens mode-locked Yb3+ -doped Lu3Al5O12 ceramic laser International conference

    Shotaro Kitajima

    CLEO/EUROPE-EQEC 2015  2015.6 

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  34. Kerr-lens mode-locked Yb3+ -doped Lu3Al5O12 ceramic laser International conference

    Shotaro Kitajima

    The 4th Advanced Lasers and Photon Sources (ALPS)  2015.4 

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    Language：English   Presentation type：Oral presentation (general)  

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  35. Highly efficient Yb3+-doped CaF2-LaF3 Ceramic Laser International conference

    Shotaro Kitajima

    CLEO  2016.6 

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  36. High Power Ultrashort Pulse Laser Based On Yb-doped Ceramic Materials International conference

    Shotaro Kitajima

    Glass and Optical Materials Division (GOMD) Meeting  2018.5 

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

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  37. CW Performance and Temperature Observation of Yb:Lu2O3 Ceramic Laser International conference

    Shotaro Kitajima

    Advanced Solid State Laser (ASSL)  2017.10 

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    Language：English   Presentation type：Poster presentation  

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  38. CW and Mode-Locked High Power Yb:Lu2O3 Ceramic Laser Invited International conference

    Shotaro Kitajima

    The 13th Laser ceramics Symposium  2017.12 

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To the head of Presentations.▲

Research Project for Joint Research, Competitive Funding, etc. 2

  1. 微細加工のための高出力・高繰り返し 超短パルス光源開発

    奨励研究助成(若手研究者枠)  

  2. 伝熱工学的アプローチによる極小熱抵抗薄ディスクレーザーの開発

    公益財団法人 池谷科学技術振興財団  公益財団法人 池谷科学技術振興財団2022年度 単年度研究助成 

To the head of Research Project for Joint Research, Competitive Funding, etc..▲

KAKENHI (Grants-in-Aid for Scientific Research) 4

  1. 極小の熱抵抗で実現する高密度励起薄ディスクレーザー

    Grant number：22K14618  2022.4 - 2024.3

    日本学術振興会  科学研究費助成事業 若手研究  若手研究

    北島 将太朗

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    Authorship：Principal investigator 

    Grant amount：\4550000 （ Direct Cost: \3500000 、 Indirect Cost：\1050000 ）

    薄ディスクレーザーはその優れた徐熱性能と低非線形性から、現在最も高い出力の超短パルスレーザーを実現できる方式として、様々な応用に用いられている。本研究ではこの薄ディスクレーザー媒質の作製プロセスに焦点を当て、これまでを凌駕する極小の熱抵抗を実現することで、薄ディスクレーザーの更なる励起密度向上とパワースケーリングを目指す。
    具体的には(a)高熱伝導・極薄型利得媒質、(b) 超低熱抵抗接合法、(c) 合成ダイヤモンド製ヒートシンクの3点の技術を開発・採用することで、モジュール全体で0.1 K/cm2Wの熱抵抗、15 kW/cm2の励起密度耐性を目指す。

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  2. 高次機能ナノチューブファイバレーザー光源の開発と先端光計測技術への展開

    Grant number：20H00350  2020.4 - 2024.3

    日本学術振興会  科学研究費助成事業 基盤研究(A)  基盤研究(A)

    西澤 典彦, 北島 将太朗, 榊原 陽一, 周 英, 山中 真仁, 北島 将太朗, 榊原 陽一, 周 英, 山中 真仁

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    Authorship：Coinvestigator(s) 

    １．SWNTを用いた高出力超短パルスファイバレーザーの開発
    Tm-Ho共添加ファイバを利得媒質に用い，1.8-2.0um帯に可飽和吸収を示す直径1.6nmのSWNTを可飽和吸収体に用いて，全ファイバ型の高出力な超短パルスファイバレーザーを開発した．Tm-Ho共添加ファイバの採用によって，励起効率を大幅に向上することができた．
    ２．SWNTを用いた全偏波保持デュアルコムファイバレーザーの開発と広帯域デュアルコム分光への応用
    1.55um帯で可飽和吸収特性を示す直径1.25nmのSWNTを用いて，全偏波保持型のEr添加デュアルコムファイバレーザーを開発した．更にその出力を増幅し，スペクトルを拡げて波長1.5um帯に吸収を持つHCNの指紋スペクトルのデュアルコム分光を実現した．システムは長期安定性に優れ，平均化によって信号対雑音比を大きく向上することができた．次に，デュアルコムファイバレーザーの出力を増幅後，波長シフトとスペクトル圧縮を行い，波長1.6～1.7umの広い帯域に渡ってCH4の指紋スペクトルのデュアルコム分光測定を実現した．また，光学系の温度制御と外乱の除去によって，測定系の安定化を図れることを示した．
    ３．スペクトルピーキング現象の発現
    上記の実験の中で，ガスの細い吸収を受けた超短パルスを光ファイバに導波させることで，吸収がピークに周期的に変換される新しい現象を見いだした．更に，数値解析と実験による解析によって諸特性とその原理を明らかにした．この技術は，数百GHzの広い周波数間隔の光周波数コムの生成や特定のコムモードの抽出，光スペクトル標準として有用である．

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  3. Development of high-power ultrashort pulsed laser with gain narrowing suppression by spatial wavelength distribution

    Grant number：20K15192  2020.4 - 2022.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Early-Career Scientists

    Shotaro Kitajima

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    Authorship：Principal investigator 

    Grant amount：\4030000 （ Direct Cost: \3100000 、 Indirect Cost：\930000 ）

    This study proposes a novel method to suppress gain narrowing and enable an industrially useful high-power ultrashort pulse laser source. The design had to be changed according to the results of numerical analysis, and actual amplification of ultrashort laser pulses could not be achieved during the research period. However, we achieved the highest output power (138 W) for a laser using Yb:KREW crystals in CW oscillation and developed a disk module that is capable of withstanding high pumping intensities of 7 kW/cm2. The disk module is expected to be of great value in the development of high-power ultrashort laser oscillators and amplifiers. We will use the obtained disk module for the amplification of ultrashort pulsed lasers, which is the original purpose of the project, as well as for proof of concept.

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  4. High Power Urtrashort Pulse Laser Based On Yb-doped Ceramic Materials

    Grant number：18J10670  2018.4 - 2020.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows  Grant-in-Aid for JSPS Fellows

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To the head of KAKENHI (Grants-in-Aid for Scientific Research).▲
 

Teaching Experience (On-campus) 5

  1. Quantum Mechanics with Exercises

    2022

  2. 電気電子情報工学実験第1

    2022

  3. 電気電子情報工学実験第2

    2022

  4. 量子力学および演習

    2021

  5. 電気電子情報工学実験第2

    2021

To the head of Teaching Experience (On-campus).▲