Composite-Phase Spin-Multiplexed Metasurface for Multi-Channel Perfect Vortex Vector Beams

Abstract

To meet the increasing demands of high-speed, high-capacity data transmission in 5G commercialization, vortex beams carrying orbital angular momentum (OAM) have emerged as a promising approach for introducing additional multiplexing dimensions. In this work, a spin-multiplexed metasurface based on a composite-phase modulation mechanism is proposed and numerically verified. Rectangular GaAs nanofins enable independent phase control of left- and right-handed circularly polarized light, integrating the functions of a vortex plate, axicon, and Fourier transform lens into a single metasurface. The results demonstrate that the designed metasurface can generate a four-channel perfect vortex vector light beams. This work presents a compact and efficient optical platform for OAM multiplexing, with broad application potential in high-speed optical communications, multidimensional optical sensing, and optical particle manipulation.