Tunable topological edge states in valley photonic crystals via liquid crystals

Valley photonic crystals (VPCs) hold significant potential for electromagnetic (EM) device applications; however, their fixed structural parameters restrict practical versatility, highlighting a critical need for dynamic control. This research investigates a tunable valley topological photonic crystal (TPC) integrated with liquid crystals (LCs). By electrically modulating the permittivity of the LCs via applied bias voltages, we realize frequency-selective topological edge states (TESs) that exhibit robust and chiral propagation characteristics. Furthermore, by analyzing the correlation between the propagation directionality and the Stokes parameters of the eigenmodes, the excitation position of the chiral source is optimized to achieve polarization-directed chiral propagation. This approach demonstrates an electrically tunable TPC device, presenting an efficient and versatile strategy for active EM manipulation and polarization control in prospective topological photonic systems.