Tunable lithium niobate metasurfaces for phase-only modulation based on quasi-bound states in the continuum.

Conclusions: We have proposed and theoretically analyzed an electro-tunable extreme Huygens’ BIC metasurface consisting of LiNbO₃ elliptical cylinders. After optimizing the geometry parameter of the structure, we have realized over 2π phase retardation of transmitted light while maintaining over 96% transmission amplitude. The metasurface can be continuously tuned based on the EO property of the LiNbO₃ without a drastic change in the transmission. The proposed LiNbO₃ metasurface will be a good candidate for developing reconfigurable optical components in optical wavefront shaping, displaying, and other applications. [ABSTRACT FROM AUTHOR]