Spin-Decoupled Metasurface for Orbital Angular Momentum Multiplexing

Orbital angular momentum (OAM) has aroused great interest of researchers due to its ability to increase communication capacity in wireless communication. Pancharatnam-Berry (PB) phase and propagation phase can be adjusted separately for circular polarized and linear polarized. However, the PB phase can only control the cross-polarized component but not the co-polarized component. Here we can simultaneously generate cross-polarized and co-polarized vortex waves carrying different OAM modes by combining PB phase and propagation phase. The developed metasurface (MS) can realize multiple OAM beams (with required directions, modes and polarized states). By adjusting the polarized state of the incident wave, different OAM modes and beam directions are demonstrated in the reflection channels. The MS have potential prospects in high-capacity wireless communications.