Electro-optic modulation using lithium niobate metasurfaces with topological corner state

Electro-optically (EO) tunable metasurfaces have received considerable attention owing to their capability for dynamic light field control. Here, we report an EO lithium niobate metasurface mediated by topological corner states. Such a supercell of metasurface is constructed by two kinds of finite-sized arrays possessing different topological properties via the generalized two-dimensional (2D) Su–Schrieffer–Heeger model. The generated narrow-linewidth resonance with high-quality factor and strong field localization are very suitable for EO modulation. The results reveal that the required driving external voltage to fully shift the resonance can be well below 15 V. Furthermore, the 0.46 rad of phase modulation is also demonstrated along with transmission intensity modulation. The results offer a fundamental path of potential for tunable displays, light detection, spatial light modulators, and Floquet topological metasurfaces.