Realization of Chiral Whispering Gallery Mode Cavities Enabled by Photonic Chern Insulators

Abstract Recently, whispering gallery modes (WGMs) have attracted considerable attention due to their extensive applications in the development of on‐chip microcavities, high‐sensitivity sensors, and high‐performance lasers. Conventional WGMs are achiral under the time‐reversal symmetry, and show high sensitivity to defects in optical devices. Here, topological physics is introduced into photonic cavities and the realization of chiral WGMs is demonstrated enabled by photonic Chern insulators. Through comprehensive numerical simulations and experimental measurements, the critical differences between chiral and achiral WGMs are revealed, highlighting the robustness of chiral WGMs even in the presence of defects within the cavities. This research provides valuable insights into the design of robust WGM cavities and offers a novel platform for exploring light–matter interaction phenomena.