Multichannel wavefront manipulation in full-space enabled by polarization multiplexing transmission-reflection switchable terahertz metasurface

Abstract A polarization multiplexing terahertz (THz) metasurface is proposed. Through ingenious selection of unit structures and precise phase arrangement, multichannel wavefront manipulation in full-space is realized. Assisted by the phase-change characteristics of vanadium dioxide, the metasurface can dynamically switch between the transmission and reflection operating modes. When the metasurface works in transmission mode, linearly polarized (LP) THz waves with different polarization directions will be converted into double-focused beams, Bessel beams or their superposition. When the metasurface works in reflection mode, THz waves propagating along -z-direction or z-direction with different polarization states, such as left-handed circularly polarized (LCP), right-handed circularly polarized (RCP), and LP, will be converted into vortex beams with different modes, different quantities, and different distribution forms. Compared with some results previously reported, the metasurface proposed has relatively obvious advantages in function integration, operating mode, and multichannel multiplexing.