Coexistence of Fano and electromagnetically induced transparency resonance line shapes in photonic topological insulators

Abstract

Due to the bending resistance and defect immunity of the topological optical structure, topological photonics is extended to researching Fano line shapes or electromagnetically induced transparency-like (EIT-like) line shapes. In this paper, two-dimensional photonic crystal with Kekule´ distortion is designed to realize quantum spin Hall effect and quantum valley Hall effect simultaneously. The stable topological corner states and edge states are obtained. Corner states as dark modes interfere with edge states as bright mode to induce Fano or EIT-like line shapes. As far as we know, we first realize the coexistence of Fano and EIT-like line shapes based on the coexistence of quantum spin Hall effect and quantum valley Hall effect. Our results provide a new way to realize multi-channel sensing technology.