Optimization and robustness of the topological corner state in second-order topological photonic crystals

The second-order topological photonic crystal with 0D corner state provides a new way to investigate cavity quantum electrodynamics and develop nanophotonic devices diverse functionalities. Here, we report on the optimization robustness of in both theory experiment. nanocavity is formed based 2D generalized Su-Schrieffer-Heeger model. quality factor optimized theoretically experimentally by changing gap between two crystals or just modulating position size airholes surrounding corner. fabricated factors are further surface passivation treatment which reduces absorption. A maximum about 6000, highest value ever reported for active state. Furthermore, demonstrate against strong disorders including bulk defect, edge even defect. Our results lay solid foundation investigations applications state, such as investigation coupling regime development optical circuitry.