A Dual-Functional Transmissive Terahertz Metasurface for Linear-to-Circular and Linear Polarization Conversion

In this paper, we propose a terahertz (THz) metasurface that can efficiently achieve both linear-to-circular polarization conversion (LCPC) and linear polarization conversion (LPC) in two different wavebands. Simulation results show that y-polarized waves at 0.276 similar to 0.391 THz are converted to right circularly polarized (RCP) wave with a transmission axis ratio less than 3dB after penetrating the metasurface. The relative bandwidth of LCPC is 34.5%, while the polarization extinction ratio (PER) of RCP is above 20dB. y-polarized waves at 0.395 similar to 0.629 THz are cross-polarized after penetrating the metasurface with polarization conversion rate (PCR) higher than 80%.