Flexible manipulation of perfect vortex beams with high reflection efficiency through the all-dielectric metasurface

we design and realize perfect vortex beam with high reflection efficiency of 90.17% by an all-dielectric metasurface through PB phase modulation structure. Flexible manipulation of topological charge and ring diameter can be achieved by modulating different parameters. In addition, we also demonstrate the generation of a 4-channel perfect vortex beam array based on the Dammann grating, with a beam uniformity of 40%.