ASAKAWA Kanta

Affiliation

Faculty of Engineering, Division of Intelligent Systems Engineering

Job Title

Assistant Professor


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Degree 【 display / non-display 】

  • Doctor (Engineering) - The University of Tokyo

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Campus Career 【 display / non-display 】

  • 2025.4
    　
    　

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Intelligent Systems Engineering   Assistant Professor  

  • 2019.3
    -
    2019.9

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Intelligent Systems Engineering   Assistant Professor  

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Papers 【 display / non-display 】

  • Pulse-to-pulse Ultrafast Dynamics of Highly Photoexcited Ge2Sb2Te5 Thin Films

    62 ( 2 )   022001   2023.2

    DOI Web of Science CiNii Research

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    Language：English   Publishing type：Research paper (scientific journal)   Joint Work  

  • Terahertz-Field-Driven Scanning Tunneling Luminescence Spectroscopy

    Kimura, K; Morinaga, Y; Imada, H; Katayama, I; Asakawa, K; Yoshioka, K; Kim, Y; Takeda, J

    ACS PHOTONICS   8 ( 4 )   982 - 987   2021.4

    DOI Web of Science

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Joint Work  

  • Observation of STM-luminescence induced by THz-field-driven tunneling electrons

    Kimura Kensuke, Morinaga Yuta, Imada Hiroshi, Katayama Ikufumi, Asakawa Kanta, Yoshioka Katsumasa, … Show more authors

    Abstract book of Annual Meeting of the Japan Society of Vacuum and Surface Science   2021 ( 0 )   2Cp05R   2021

    DOI CiNii Research

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Vacuum and Surface Science   Joint Work  

    <p>In this work, we developed a novel nano-spectroscopy technique, entitled terahertz-field-driven scanning tunneling luminescence (THz-STL) spectroscopy, based on a scanning tunneling microscope (STM). THz-STL spectroscopy combines two cutting-edge STM techniques, THz-STM and STL spectroscopy, and enables to investigate atomic-scale energy dissipations triggered by a THz single-cycle pulse. We introduced single-cycle THz pulses into an STM junction (Au tip and Ag(111)) and measured visible photons generated by THz-field-driven electrons. By utilizing this technique, we detected the radiative decay of a localized plasmon excited by THz-field-driven electrons and clarified mechanistic differences in plasmon excitation between field- and DC-driven electrons.</p>

  • Nanoscale phase change on Ge2Sb2Te5 thin films induced by optical near fields with photoassisted scanning tunneling microscope

    Asakawa Kanta, Kim Dang-il, Yaguchi Shotaro, Mikito Tsujii, Katsumasa Yoshioka, Kaneshima Keisuke, … Show more authors

    Applied Physics Letters   117 ( 21 )   211102   2020.11

    DOI Web of Science CiNii Research

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Institute of Physics   Joint Work  

    A scanning probe microscope coupled with either femtosecond laser pulses or terahertz pulses holds great promise not only for observing ultrafast phenomena but also for fabricating desirable structures at the nanoscale. In this study, we demonstrate that a few-nanometer-scale phase change can be non-thermally stored on the Ge2Sb2Te5 surface by a laser-driven scanning tunneling microscope (STM). An atomically flat Ge2Sb2Te5 surface was irradiated with the optical near-field generated by introducing femtosecond laser pulses to the STM tip-sample junction. The STM topographic images showed that few-nanometer-scale mounds appeared after irradiation. In addition, tunneling conductance spectra showed that the bandgap increased by 0.2 eV in the area of 5 × 5 nm2. These indicate that the nanoscale crystal-to-amorphous phase change was induced by the STM-tip-induced near field. Our approach presented here offers an unprecedented increase in the recording density of optical storage devices and is, therefore, expected to facilitate the development of next-generation information technology.

  • Surface Science and Vacuum Science Related to Laser Cooling Methods and Optical Lattice Clocks

    OHNO Shinya, ASAKAWA Kanta

    Vacuum and Surface Science   63 ( 10 )   512 - 513   2020.10

    DOI CiNii Research

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Vacuum and Surface Science   Joint Work  

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Presentations 【 display / non-display 】

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