Robust Fano resonance induced by topologically protected interface modes interference at gigahertz

Abstract We theoretically realize a highly robust Fano resonant structure. The occurrence of robust Fano resonance can be caused by the coupling of topological bright interface mode and topological dark interface mode at the interface between trivial and non-trivial insulators. Through the research of band structure, it is confirmed that the structure has the characteristic of specific band inversion, which can realize the topological phase transition. In addition, we verify that the Fano resonance is still robust in horizontal and vertical perturbations, which is significant for designing Fano-based devices to solve issues caused by manufacturing.