Photonic crystal nanocavity based on a topological corner state

Yasutomo Ota, Feng Liu, Ryota Katsumi, Katsuyuki Watanabe, Katsunori Wakabayashi, Yasuhiko Arakawa, Satoshi Iwamoto

Research output: Contribution to journalArticlepeer-review

278 Citations (Scopus)


Topological photonics has emerged as a novel approach to engineering the flow of light and provides unprecedented means for developing diverse photonic elements, including robust optical waveguides immune to structural imperfections. However, the development of nanoscale standing-wave cavities in topological photonics is rather slow, despite its importance when building densely integrated photonic integrated circuits. In this Letter, we report a photonic crystal nanocavity based on a topological corner state, supported at a 90-deg-angled rim of a twodimensional photonic crystal. A combination of the bulk-edge and edge-corner correspondences guarantees the presence of the higher-order topological state in a hierarchical manner. We experimentally observe a corner mode that is tightly localized in space while supporting a high Q factor over 2,000, verifying its promise as a nanocavity. These results cast new light on the way to introduce nanocavities in topological photonics platforms.

Original languageEnglish
Pages (from-to)786-789
Number of pages4
Issue number6
Publication statusPublished - 2019 Jun 20
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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