Generation of generalized perfect vortex beam based on dielectric spin-multiplexed metasurface

The perfect vortex beam (PVB) possesses an annular intensity profile diameter independent of topological charge, which has attracted much attention owing to the ability of improving optical fiber transmission efficiency. The composite PVB (CPVB) is mainly based on the superposed multiple Laguerre-Gaussian beams with specific polarization states, which possesses topological charge-relevant spot shaped intensity pattern and the topological charge-irrelevant profile diameter. A series of spin-multiplexed metasurfaces have been designed to generate different PVB and CPVB under different spin light. The CPVB can also be modulated in scaling and rotating manner, which can broaden the dimensions of information. A spin-multiplexed metasurface has also been designed to generate CPVB array with different rotation angles and spot number under different spin light, and the encoding process has also been demonstrated. The uniqueness of these metasurfaces makes this design philosophy very attractive for applications in spin photonics, information encryption, optical communication, and optical information storage.