Valley-Polarized Plasmonic Edge Mode Visualized in the Near-Infrared Spectral Range

Hikaru Saito, Daichi Yoshimoto, Yuto Moritake, Taeko Matsukata, Naoki Yamamoto, Takumi Sannomiya

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Valley polarization has recently been adopted in optics, offering robust waveguiding and angular momentum sorting. The success of valley systems in photonic crystals suggests a plasmonic counterpart that can merge topological photonics and topological condensed matter systems, for instance, two-dimensional materials with the enhanced light-matter interaction. However, a valley plasmonic waveguide with a sufficient propagation distance in the near-infrared (NIR) or visible spectral range has so far not been realized due to ohmic loss inside the metal. Here, we employ gap surface plasmons for high index contrasting and realize a wide-bandgap valley plasmonic crystal, allowing waveguiding in the NIR-visible range. The edge mode with a propagation distance of 5.3 μm in the range of 1.31-1.36 eV is experimentally confirmed by visualizing the field distributions with a scanning transmission electron microscope cathodoluminescence technique, suggesting a practical platform for transferring angular momentum between photons and carriers in mesoscopic active devices.

Original languageEnglish
Pages (from-to)6556-6562
Number of pages7
JournalNano Letters
Issue number15
Publication statusPublished - Aug 11 2021

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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