Topological Cavity Chains via Shifted Photonic Crystal Interfaces

Recent advances in topological photonics provide unprecedented opportunities to realize a photonic cavity. A recent work shows that the electromagnetic wave can be effectively trapped via the shifted photonic crystal interfaces (SPCIs), which offers an alternative approach to realizing the photonic cavity. Here, we proposed one-dimensional topological insulators based on an SPCIs-induced cavity chain, which is analogous to the Su–Schrieffer–Hegger model and is compatible with the silicon-on-insulator platform. Owing to the asymmetry feature of SPCIs-induced cavities, the topological cavity chains can be either realized by alternating the cavity modes or by tuning the distance between two cavities. The nontrivial band topology of SPCIs-induced cavity chains is further confirmed by observing topological end states, which exhibit robustness against geometrical imperfections. Our work holds promises for designing robust photonic devices, which may find potential applications in future integrated photonics.