High-efficiency electrically tunable active metasurfaces

We theoretically demonstrate electrically tunable metasurfaces, which can dynamically manipulate the wavefront of the reflected light in the near-infrared wavelength range with optical efficiencies > 80%. We achieve a dynamically tunable optical response by integrating a lithium niobate l(LNO) layer into the silicon-based resonant metasurface structure. By applying voltage, we achieve a dynamically tunable phase shift of 236 degrees when the refractive index of the LNO layer varies between 2.208 and 2.212. Finally, we analyze the beam steering performance of the designed metasurfaces. The designed metasurfaces could be useful for free space optical communications, light detection and ranging (LiDAR), and laser-based additive manufacturing.