Tunable anisotropic metasurface by utilizing phase change material in terahertz range

Due to the capability of achieving versatile control of differently polarized electromagnetic waves, anisotropic metasurfaces have attracted extensive attentions. To manipulate terahertz waves flexibly, we propose a tunable anisotropic metasurface based on phase change material vanadium dioxide (VO2). It is composed of a gold bottom layer deposited on the back of polyimide dielectric layer and a gold patch located on the front of the polyimide dielectric substrate. When VO2 is in the insulating state, the predesigned metasurface produces diversified functions, including terahertz beam splitting, deviation focusing, and multivortex beam under different polarization terahertz wave incidence. When VO2 becomes a metallic state, the proposed metasurface changes the number of terahertz beams, the shape of vortex beams, and the focusing effect. This scheme provides an innovative idea for the dynamic regulation of the terahertz wave in future terahertz technology systems.