Multi-channel and multi-function terahertz metasurface

Generally, one of the disadvantages of the reported metasurface is single-channel, which affects its practical application in multiplexing system. To overcome this shortage, a reflected shared-aperture metasurface is proposed to produce multi-channel and multifunction. The unit cell consists of a square metal strip silicon dioxide substrate and a metal plate bottom layer. Based on geometrical phase theory, 0∼2π phase shift can be covered by rotating orientation angles of the top metal strip. The designed metasurface realizes multi-channel and multi-function including four-channel deflected beams with different angles, dual-channel vortex beams with different topological charges, and dual-channel vortex focusing beams under right-handed circularly polarized (RCP) wave incidents. Our investigation offers a simple and effective approach to design high-efficiency terahertz wavefront manipulation devices.