An Optical Cavity Based on Valley Photonic Topological Insulator
Yandong Li, Yang Yu, Liu Feng-yu, Gennady Shvets · 2019
We demonstrate optical energy localization of a topologically protected unidirectional mode inside a cavity. The structure is reciprocal and requires no external magnetic field. The energy is localized in a subwavelength zero-dimensional mode. We use the coupled mode theory to analyze the interaction between the topological waveguide mode and the cavity mode. The analytic model matches perfectly with the results from first-principles simulations. Our design offers a new way of building resonate cavities by exploiting the unidirectionality of topological nontrivial photonic modes.