Independently regulating linearly and circularly polarized terahertz wave metasurface

Abstract

We propose a terahertz metasurface that can independently regulate linearly circularly polarized waves. It consists of the top layer “O-O” metal pattern, polyimide layer, middle layer “I” shaped metal pattern, polyimide layer, and metal substrate from top to bottom. By using the phase principle of Pancharatnam Berry (PB) for encoding and arrangement, the metasurface generates vortex beams with different topological charges under circularly polarized terahertz wave incidence, and achieves focusing shift at different positions. Combining the convolution theorem for encoding arrangement, the metasurface can achieve focused vortex function under circularly polarized terahertz wave incidence. The designed metasurface can also generate Airy beam under linearly polarized terahertz wave incidence. The simulation results indicate that under different polarization (linear/circular polarization) terahertz wave incidence, the metasurface can achieve different functions, which provides a new approach for flexible control of terahertz waves.