Updated on 2022/03/30

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

Degree 1

  1. 博士(工学) ( 2019.3   電気通信大学 ) 

Research Interests 5

  1. ファイバーレーザー

  2. モード同期レーザー

  3. 固体レーザー

  4. 薄ディスクレーザー

  5. 超短パルスレーザー

Research Areas 1

  1. Nanotechnology/Materials / Optical engineering and photon science

Research History 2

  1. Nagoya University   Graduate School of Engineering Electronics   Assistant Professor

    2021.10

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    Country:Japan

  2. Osaka University   Institute of Laser Engineering   Designated assistant professor

    2019.4 - 2021.9

Education 2

  1. The University of Electro-Communications

    2014.4 - 2019.3

  2. Nagano National College of Technology

    2007.4 - 2012.3

Professional Memberships 2

  1. 日本レーザー学会

    2014

  2. Optica

Committee Memberships 1

  1. レーザー学会中部支部   庶務幹事  

    2021.10   

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    Committee type:Academic society

Awards 5

  1. 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

  2. “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

  3. “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

  4. “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

  5. 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

 

Papers 9

  1. 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

    Web of Science

    Scopus

    PubMed

  2. 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

    Web of Science

    Scopus

    PubMed

  3. 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.

    Scopus

  4. 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

    PubMed

  5. 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

    Scopus

  6. 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

    Web of Science

    PubMed

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

  7. 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

    Scopus

  8. 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

    Web of Science

    PubMed

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

  9. 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%.

    Web of Science

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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  

    CiNii Books

Presentations 22

  1. 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)  

  2. 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)  

  3. 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)  

  4. 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)  

  5. 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)  

  6. 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)  

  7. 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)  

  8. 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  

  9. 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  

  10. 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)  

  11. 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  

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

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

    Shotaro Kitajima

    CLEO  2016.6 

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    Language:English   Presentation type:Oral presentation (general)  

  14. 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 

  15. 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)  

  16. 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)  

  17. 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)  

  18. 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)  

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

    Shotaro Kitajima

    CLEO/EUROPE-EQEC 2017  2017.6 

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    Language:English   Presentation type:Oral presentation (general)  

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

    Shotaro Kitajima

    CLEO  2018.5 

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    Language:English   Presentation type:Oral presentation (general)  

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

    Shotaro Kitajima

    CLEO/EUROPE-EQEC 2015  2015.6 

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    Language:English   Presentation type:Oral presentation (general)  

  22. 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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Research Project for Joint Research, Competitive Funding, etc. 1

  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)  

KAKENHI (Grants-in-Aid for Scientific Research) 2

  1. 空間波長分布により利得狭窄を抑制した高出力超短パルスレーザーの開発

    Grant number:20K15192  2020.4 - 2022.3

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

    高出力な超短パルスレーザーは微細精密加工などの産業分野をはじめ幅広い応用があるが、利得狭窄という現象により高い出力と短いパルス幅の両立はこれまで困難とされてきた。本研究ではこの利得狭窄を補償し、フェムト秒 (10-15秒)のパルス幅と高い出力を併せ持った超短パルスレーザーを開発することを目的とする。具体的には共振器中に回折格子を組み込んだ新規コンセプトの利得狭窄抑制レーザー増幅器を提案する。本研究ではまず利得媒質モジュールと励起光学系の開発を行い、次にそれらを用いた増幅器を構築することで本コンセプトの原理実証を行う。
    高出力な超短パルスレーザーは微細精密加工などの産業分野をはじめ幅広い応用があるが、利得狭窄という現象により高い出力と短いパルス幅の両立はこれまで困難とされてきた。本研究ではこの利得狭窄を補償し、フェムト秒 (10-15秒)のパルス幅と高い出力を併せ持った超短パルスレーザーを開発することを目的とする。具体的には共振器中に回折格子を組み込んだ新規コンセプトの利得狭窄抑制レーザー増幅器を提案する。これによりレーザー光は共振器中で波長成分ごとに分割され、励起レーザーの空間強度変調と組み合わせることで、スペクトルの狭帯域化を抑制する。本研究ではまず利得媒質モジュールと励起光学系の開発を行い、次にそれらを用いた増幅器を構築することで本コンセプトの原理実証を行う。
    本年度は主に薄ディスクレーザーの励起モジュールの構築と、薄ディスクの製造、また利得媒質の励起下の温度分布などの計算を行った。まず励起モジュールの構築では、放物面鏡とプリズムミラーを用いた励起光学系を構築し、アライメントのズレなくファイバー結合型半導体レーザーの出射光をディスク上に集光することに成功した。次に薄ディスクの製造では、業者と連携し、Yb添加のタングステート系材料にて厚さ300umの研磨とコートを行った。温度分布の計算では、熱流体FEM計算を用いた詳細な温度分布の計算を行い、低熱伝導率材料でありながら、概ね200W程度の励起に耐えられることを確認した。
    以上の工程により、次年度からの薄ディスクレーザーを用いたレーザー発振及び増幅実験の準備が整った。
    以上のように難関だと思われた薄ディスクレーザーの励起光学系や利得モジュールの製造に成功し、次年度からの発振器及び増幅器の構築に遅延なく進めるため。
    薄ディスクレーザーにて発振器及び増幅器の構築をし、当初の目的である空間波長分散を用いた利得狭窄の補償に取り組む

  2. 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

 

Teaching Experience (On-campus) 2

  1. 量子力学および演習

    2021

  2. 電気電子情報工学実験第2

    2021