Characterization of overlapped plasmon modes in a gold hexagonal plate revealed by three-dimensional near-field optical microscopy

Takuya Matsuura, Keisuke Imaeda, Seiju Hasegawa, Hiromasa Suzuki, Kohei Imura

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2 Citations (Scopus)


A detailed characterization of plasmon modes is important not only for a deeper understanding of plasmons but also for their practical applications. In this study, we investigated the three-dimensional near-field characteristics of high-order plasmon modes excited in a gold hexagonal nanoplate. From the near-field spectroscopic images, we found that both in-plane and out-of-plane plasmon modes observed near 900 nm were spectrally and spatially overlapped. We performed three-dimensional near-field measurement to reveal the optical characteristics of the overlapped modes in detail. We found that the steric near-field distribution near the nanoplate strongly depended on the plasmon mode, and the out-of-plane mode confines electromagnetic fields more tightly than the in-plane mode. We also found that the in-plane mode was dominantly visualized as the probe tip-sample distance increased. These findings demonstrate that the three-dimensional near-field technique enables selective visualization of a single plasmon mode even if multiple modes are spatially and spectrally overlapped.

Original languageEnglish
Pages (from-to)819-824
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number4
Publication statusPublished - 2019 Feb 21


ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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