Hasegawa, Taro

写真a

Affiliation

Faculty of Science and Technology, Department of Physics (Yagami)

Position

Assistant Professor/Senior Assistant Professor

E-mail Address

E-mail address

Related Websites

External Links

Career 【 Display / hide

  • 1996.04
    -
    2000.09

    Research Associate, Dept. Electronics and Computer Science, Science Univ. of Tokyo in Yamaguchi

  • 2000.09
    -
    2005.03

    Research Associate, Dept. of Material Science, Faculty of Science, Himeji Institute of Technology (The institute was united and renamed as "Univ. of Hyogo" from Apr. 2004.)

  • 2003.01
    -
    2004.03

    Guest Researcher, Time and Frequency division, National Institute of Standards and Technology (NIST), United States of America

  • 2005.04
    -
    Present

    Assistant Professor, Dept. Physics, Fac. Sci.&Tech., Keio Univ.

  • 2010.07
    -
    2010.09

    Guest Researcher (Max-Planck-Institut fuer Quantenoptik)

display all >>

 

Research Areas 【 Display / hide

  • Atomic/Molecular/Quantum electronics (Atomic/Molecular/Quantum Electronics, Plasma)

Research Keywords 【 Display / hide

  • Ion traps

  • Laser cooling

  • Optical Frequency Comb Generators

  • Nonlinear Optics

  • High-resolution spectroscopy

Research Themes 【 Display / hide

  • 大きな蛍光観測立体角をもつイオントラップの開発, 

    2015.04
    -
    Present

  • 光周波数コムを用いた高分解能分光, 

    2013.04
    -
    Present

  • New ion-trapping scheme for quantum computing, 

    2004
    -
    2005

     View Summary

    Implementation of quantum computers using the quantum states of ions
    in a new ion trap.

 

Books 【 Display / hide

  • ペンギン物理学辞典

    清水忠雄ほか合計21名, 朝倉書店, 2012

  • 光学実験の基礎と改良のヒント

    UEHARA KIYOJI, HASEGAWA TARO, SASADA HIROYUKI, 講談社サイエンティフィク, 2009

    Scope: 63-112

Papers 【 Display / hide

  • Robust offset locking of laser frequency with electronically tunable LC circuits for sub-millihertz uncertainty

    Yuhei Seishu, Taro Hasegawa

    Applied Physics B (Springer)  125 ( 8 ) 142(1) - 142(8) 2019.07

    Research paper (scientific journal), Joint Work, Accepted

  • Mode Density Multiplication of an Optical Frequency Comb by N^{2} with Phase Modulation

    Hasegawa T., Sasada H.

    2018 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2018 (2018 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2018)   2019.04

    ISSN  9781943580453

     View Summary

    © 2018 OSA. We introduce a simple scheme for mode density multiplication of an optical frequency comb by square of an arbitrary integer with phase modulation. The mode density of an Er fibercomb is multiplied by 4 2 .

  • Mode density multiplication of an optical frequency comb by N<sup>2</sup> with phase modulation

    Hasegawa T.

    Optics Express (Optics Express)  26 ( 19 ) 24551 - 24563 2018.09

     View Summary

    © 2018 Optical Society of America. We introduce a simple scheme for mode-density multiplication of an optical frequency comb (OFC) by a factor of square of an arbitrary integer N using phase modulation. This scheme is employed to multiply the mode density of an erbium-doped fiber laser OFC (repetition rate of 66.87 MHz) by factors of 42, 82, and 3 · 42 using an electro-optic phase modulator. The OFC multiplied by 42 is applied to direct-comb spectroscopy of methane with a spectral resolution of 4.18 MHz.

  • A radio-frequency ion trap with string electrodes

    KANAI DAISUKE, HASEGAWA TARO

    Review of Scientific Instruments (American Institute of Physics)  89 ( 2 ) 023106 2018.02

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  00346748

     View Summary

    © 2018 Author(s). A radio-frequency (rf) ion trap with string electrodes is introduced. In this trap configuration, the rf electrodes are made of narrow metal strings, by which a negligibly small portion of light-induced fluorescence (LIF) is blocked. Then the LIF collection solid angle can be maximized. In the demonstration, barium ions are trapped and laser-cooled in the rf trap with string electrodes successfully, and the crystallization is confirmed by the LIF spectrum.

  • Mode density multiplication of an optical frequency comb by N <sup>2</sup> with phase modulation

    Hasegawa T., Sasada H.

    Optics InfoBase Conference Papers (Optics InfoBase Conference Papers)  Part F113-CLEOPR 2018 2018

    ISSN  9781943580453

     View Summary

    © OSA 2018 We introduce a simple scheme for mode density multiplication of an optical frequency comb by square of an arbitrary integer with phase modulation. The mode density of an Er fibercomb is multiplied by 4 2

display all >>

Papers, etc., Registered in KOARA 【 Display / hide

Reviews, Commentaries, etc. 【 Display / hide

  • 強度画像にはない位相画像の表現力 (翻訳)

    HASEGAWA TARO

    パリティ (丸善)     14 - 21 2018.02

    Introduction and explanation (commerce magazine)

Presentations 【 Display / hide

  • Robust offset locking of laser frequency with electronically tunable LC circuits for sub-millihertz uncertainty

    Taro Hasegawa, Yuhei Seishu

    2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (International Congress Centre Munich, Germany) , 2019.06, Poster (general)

  • 可変LC回路を用いた堅牢なレーザー周波数安定化法

    長谷川太郎、清酒悠平

    ERATO美濃島知的光シンセサイザプロジェクト成果報告会 (電気通信大学) , 2019.03, Poster (general)

  • 可変LC回路を用いた堅牢なレーザー周波数安定化法

    清酒悠平、長谷川太郎

    日本物理学会第74回年次大会 (九州大学) , 2019.03, Oral Presentation(general), 日本物理学会

  • Mode density multiplication of an optical frequency comb without power dissipation

    Taro Hasegawa

    KEIO Symposium on Microresonator Frequency Comb (Hong Kong Convention and Exhibition Centre, Hong Kong) , 2018.12, Oral Presentation(general)

  • 高分解能な光周波数コム直接分光

    長谷川太郎、佐々田博之

    日本物理学会2018年秋季大会 (同志社大学) , 2018.09, Oral Presentation(general), 日本物理学会

display all >>

Research Projects of Competitive Funds, etc. 【 Display / hide

  • 変位型サニャック干渉計を用いた超短パルスレーザーのパルス時間測定器

    2019.04
    -
    2020.03

    慶應義塾大学, 学事振興資金, 長谷川太郎, Research grant, Principal Investigator

  • 光周波数コムを用いた超高分解能高速高精度分光法の開発

    2019.04
    -
    2020.03

    公益財団法人精密測定技術う振興財団, 精密測定技術振興のための調査・研究事業, 長谷川太郎, Research grant, Principal Investigator

  • インコヒーレント光源の1光子吸収によるイオントラップへのイオンローディング法

    2018.04
    -
    2019.03

    慶應義塾大学, 学事振興資金, 長谷川太郎, Research grant, Principal Investigator

  • 回転rfトラップにおけるダストプラズマの挙動

    2016.04
    -
    2017.03

    慶應義塾大学, 学事振興資金, 長谷川太郎, Research grant, Principal Investigator

  • 新しい広帯域かつ狭線幅な赤外分光法

    2015.04
    -
    Present

    日本学術振興会, Grant-in-Aid for Scientific Research, 長谷川太郎, Research grant, Principal Investigator

display all >>

 

Courses Taught 【 Display / hide

  • PHYSICS LABORATORIES 2

    2019

  • PHYSICS LABORATORIES 1

    2019

  • OPTICS

    2019

  • LITERATURE OF PHYSICS

    2019

  • LASER PHYSICS

    2019

display all >>

Courses Previously Taught 【 Display / hide

  • 電磁気学第2

    慶應義塾大学, 2018

  • Optics

    Keio University, 2017, Spring Semester, Major subject, Within own faculty

  • Laser Physics

    Keio University, 2017, Spring Semester, Within own faculty

  • Optics

    Keio University, 2016, Spring Semester, Major subject, Within own faculty

  • Optics

    Keio University, 2015, Spring Semester, Major subject, Within own faculty

display all >>

 

Memberships in Academic Societies 【 Display / hide

  • Physical Society of Japan

     
  • American Physical Society

     
  • Optical Society of America

     
  • The Spectroscopical Society of Japan

     

Committee Experiences 【 Display / hide

  • 2012.04
    -
    2014.03

    Editor, Physical Society of Japan

     View Remarks

    日本物理学会誌

  • 2007.11
    -
    2008.10

    Program committee of Quantum Electronics subsection, section 1, Physical Society of Japan