Terahertz anisotropic coding metasurface based on vanadium dioxide

Terahertz (THz) wave has the advantages of high resolution, large information capacity, easy beam focusing, etc, and can be used in fields communication, radar, detection others. Firstly, as a two-dimensional artificial electromagnetic metamaterial, coding metasurface is proposed microwave band. It uses digital phase to adjust waves. Subsequently, an important way regulate THz, extends terahertz frequency band becomes research hotspot . In this paper, we design based on vanadium dioxide (VO<sub>2</sub>) with anisotropic characteristics. composed three layers, metal cross structure embedded VO<sub>2</sub> at top, polyimide middle, pure bottom. The shaped makes unit anisotropic, which provide complete independent control orthogonally linearly polarized incident bottom higher reflection amplitude for wave. And introduced into metasurface. As change material, switch its properties between insulating state metallic state, further increases flexibility THz Eight different units are designed work. They arranged according reasonable sequence form metasurface, consisits 20×20 overall size 2.4 mm × mm. Its will changed VO<sub>2</sub>, thus forming corresponding 1bit or 2bit generated changes accordingly. finite-difference time domain method modeling implementing simulation, results follows. 1-THz orthogonal vertically When regarded generate dual-polarization OAM vortex beams. <i>x</i>-polarized mode number 2, <i>y</i>-polarized possesses 1. symmetrical Four reflected waves by waves, two created combining anisotropy material realizes function generating multiple beams forms same present reference implementation multi-functional that flexibly applied scenes.