Controllable terahertz bifunctional device based on vanadium dioxide-gold metasurface

The invention discloses a controllable terahertz dual-function device based on a vanadium dioxide-gold metasurface, and relates to the technical field of terahertz metasurfaces. When vanadium dioxide is in a metal state, a broadband absorption function is achieved; when vanadium dioxide is in an insulated state, a transmission-type orthogonal line polarization conversion function is realized. The switchable vanadium dioxide-gold metasurface unit structure is composed of five layers of structures, and the five layers of structures are a closed pattern layer composed of vanadium dioxide and gold, a polycrystalline silicon dielectric layer, a vanadium dioxide thin film layer, a polycrystalline silicon dielectric layer and a double-E-shaped connecting gold pattern layer in sequence from top to bottom. According to the invention, the phase change characteristic of the vanadium dioxide material is combined with the metasurface, so that a dual-function device with active control design for broadband absorption and t