Dynamic Control of Optical Vector Beams with Reconfigurable BIC Metasurfaces

On-chip dynamic tailoring the polarization states and vortex topological charges of optical vector beams can find vital roles in miniaturized light sources and phase plates. Metasurfaces featuring bound states in the continuum (BIC) are known to generating various polarization states via structural symmetry engineering, but their dynamic tunability has not yet been demonstrated. In this study, we propose a reconfigurable vortex wave plate by integrating electrically tunable anisotropic liquid crystal medium with BIC metasurfaces. This scheme allows versatile polarization control spanning nearly the entire Poincar ́e sphere by rotating the liquid crystal molecules. Furthermore, we demonstrate active tuning of the vortex topological charges through interband coupling and band inversions. The on-chip multidimensional manipulation of the vector beam states holds great promises for applications in optical microscopy, manufacturing, and communications.