Research field (3)：
Control and systems engineering
, Applied physics - general
, Optical engineering and photonics
Research keywords (7)：
Laser physics
, Optical lattice clock
, Optical frequency comb
, Optical frequency measurement
, Frequency metrology
, Made-lock laser
, Mode-locked fiber Laser
Research theme for competitive and other funds (21)：
2021 - 2026 Second earth search by high-precision line-of-sight velocity measurement using visible ultra-broadband laser comb
2022 - 2025 Development of a high-precision method for measuring the group refractive index using a dual-comb spectral interferometer and a double-sided interferometer.
2022 - 2025 Development of a high-precision method for measuring the group refractive index using a dual-comb spectral interferometer and a double-sided interferometer.
2022 - 2025 2種の光コムの高度な制御による高速かつ高精度な分光技術の創出
2021 - 2024 Thermodynamic temperature determination by thermal radiation heterodyne detection using an optical frequency comb
2021 - 2024 超高精度多成分微量ガス分析のためのデュアルコム共振器モード分散分光法の開発
2020 - 2023 Development of a method for small mass measurements using the new definition of the kilogram based on the Planck constant
2019 - 2022 Construction of Temperature Standard Based on New Definition of SI by Optical Comb Thermometry
2017 - 2022 The realisation of an optical time scale based on optical frequency standards
2018 - 2021 High speed and high resolution spectroscopy using two types of optical frequency combs
2015 - 2020 Direct Detection of Cosmic Acceleration by TMT & High Dispersion Spectrograph
2016 - 2019 Molecular gas thermometry using dual-comb spectroscopy
2016 - 2019 Research to realize the definition of the kilogram based on the fundamental constants
2016 - 2018 Development of the polarization-sensitive dual comb spectroscopy
2015 - 2018 Dual-comb spectroscopy at visible wavelength range using Er fiber combs
2014 - 2017 Development of the ultra-stable optical cavity using a ceramic spacer
2013 - 2016 High-accuracy length metrology with self-correction of environmental fluctuation using optical frequency combs.
2011 - 2014 Development of ultra high resolution mid-infrared molecular spectrometer combining advanced sources
2011 - 2013 Absolute linewidth narrowing of optical frequency comb using an ultrastable cavity
2010 - 2012 Development of ultra-stable lasers using low-thermal-noise optical cavities
2009 - 2011 Study on absolute distance measurements of sub-wavelength accuracy using cascaded coherent link with optical combs
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Papers (230)：
Takumi Kobayashi, Akiko Nishiyama, Kazumoto Hosaka, Daisuke Akamatsu, Akio Kawasaki, Masato Wada, Hajime Inaba, Takehiko Tanabe, Masami Yasuda. Improved absolute frequency measurement of 171Yb at NMIJ with uncertainty below 2 × 10-16. Metrologia. 2025
Akiko Nishiyama, Sho Okubo, Takumi Kobayashi, Akio Kawasaki, Hajime Inaba. Measurement of transition frequencies and hyperfine constants of molecular iodine at 520.2 nm. Journal of the Optical Society of America B. 2024
Takumi Kobayashi, Daisuke Akamatsu, Kazumoto Hosaka, Yusuke Hisai, Akiko Nishiyama, Akio Kawasaki, Masato Wada, Hajime Inaba, Takehiko Tanabe, Tomonari Suzuyama, et al. Generation of a precise time scale assisted by a near-continuously operating optical lattice clock. Physical Review Applied. 2024. 21. 6
Keisuke Nakamura, Ken Kashiwagi, Sho Okubo, Hajime Inaba. Erbium-doped-fiber-based broad visible range frequency comb with a 30 GHz mode spacing for astronomical applications. Optics Express. 2023. 31. 12. 20274-20274
