Tunable trifunctional terahertz metasurface integrated with VO2-gold gratings

A tunable trifunctional metasurface for broadband polarization conversion and dual-band asymmetric transmission is proposed, in which vanadium dioxide (VO
2
) is embedded in the structure. The metasurface can operate in reflection or transmission modes by controlling the external temperature. Under the external condition of high temperature, the metasurface works in reflection mode, which can convert the linearly polarized waves (LP) and circularly polarized waves into ones cross-polarized waves at broadband with the polarization conversion ratio (PCR) of above 92%; while the external conditions are changed to room temperature, the metasurface operates in transmission mode, the forward and backward incident left-handed/right-handed circularly polarized (LCP/RCP) waves can achieve asymmetric transmission (AT) effect at 0.73 THz and 1.17 THz, respectively. The proposed metasurface holds potential prospects in controllable switch, wireless communication and so on.