Dual reconfigurable topological edge states based on spin-locked photonic crystals

Topological edge states have revolutionized our understanding of electromagnetic manipulation due to its topological robustness. Especially, reconfigurable topological photonic crystals will have desirable applications in optical devices. Here, we propose a dual reconfigurable topological insulator within a triangular lattice composed of all-dielectric Yshaped cylinders. Liquid crystals are employed to adjust the relative permittivity of background under an external electric field. As a result, topological edge states can be dynamically regulated by using liquid crystals to manipulate photonic dispersions. Meanwhile, the topological transitions between trival phase and nontrival phase are accomplished by rotating the Y-shaped scatters. Furthermore, the reconfigurable pathways of topological edge states are further demonstrated. Our work offers a new way for flexible manipulation of electromagnetic wave transmission, which will have potential applications in Terahertz and optical communication systems.