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October 14, 2022
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October 14, 2022

Observation of surface plasmon excitation/relaxation processes of nanoparticles

Key Points:
  • Time-resolved electron microscopy using a 100 kV laser-driven photocathode electron gun.
  • Picosecond time-resolved measurements of the photoexcited relaxation processes of surface plasmons on gold nanoparticles using electron energy-loss spectroscopy with pulsed electron probes.
  • The relaxation times of photo-excited nanoparticles were successfully measured.
Dr. Shota Kuwahara
Summary In a joint research project, a research group including Dr. Shota Kuwahara from the Faculty of Science, Toho University, successfully investigated relaxation processes using energy loss peak intensities, positions, and widths in electron energy loss spectroscopy with a picosecond-pulsed electron probe. Using this method, the relaxation times of photoexcited nanoparticles were measured and from that the temperature change over time was successfully estimated. Thus, energy-loss spectroscopy using pulsed electron beams was adapted and applied to plasmonic materials. This study presents the realization of a new time-resolved nano-measurement system through an industry-academia collaboration. It is also expected to be adapted to the measurement of optical energy conversion processes of plasmonic materials and the localized thermal relaxation nano-measurement of thermoelectric conversion materials. The results of this research were published in the scientific journal Applied Physics Letters on 6 October 2022.
Dr. Shota Kuwahara
Summary
In a joint research project, a research group including Dr. Shota Kuwahara from the Faculty of Science, Toho University, successfully investigated relaxation processes using energy loss peak intensities, positions, and widths in electron energy loss spectroscopy with a picosecond-pulsed electron probe. Using this method, the relaxation times of photoexcited nanoparticles were measured and from that the temperature change over time was successfully estimated. Thus, energy-loss spectroscopy using pulsed electron beams was adapted and applied to plasmonic materials. This study presents the realization of a new time-resolved nano-measurement system through an industry-academia collaboration. It is also expected to be adapted to the measurement of optical energy conversion processes of plasmonic materials and the localized thermal relaxation nano-measurement of thermoelectric conversion materials. The results of this research were published in the scientific journal Applied Physics Letters on 6 October 2022.

Figure 1: Experimental setup for transient EELS in the time-resolved transmission electron microscope, the pump-probe system and the obtained intensity mapping of EELS as functions of time and loss energy

Journal:
Applied Physics Letters

Title:
Transient electron energy-loss spectroscopy of optically stimulated gold nanoparticles using picosecond pulsed electron beam

Authors:
Makoto Kuwahara (Nagoya University),Lira Mizuno(Nagoya University), Rina Yokoi (Nagoya University),Hideo Morishita (Nagoya University), Takafumi Ishida (Nagoya University), Koh Saitoh(Nagoya University), Nobuo Tanaka(Nagoya University), Shota Kuwahara(Toho University), and Toshihide Agemura(Hitachi High-Tech Corporation,)

DOI No.
10.1063/5.0108266

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