Dynamically reconfigurable topological states in photonic crystals with liquid crystals

Dynamically tunable and reconfigurable topological states are realized in higher-order topological insulators with the liquid crystal (LC). By changing the loading voltage of the LC, the eigenfrequency of the edge and corner states can be tuned, but even more important is that the edge state and corner state with the same frequency are realized. Based on this reconfigurability of topological states, optical routers and lasers with multiple topological states can be realized. Our results may be applied to topological optical circuits and provide new ideas for optical field localization and manipulation.