Generation and control of high-reflection-efficiency perfect vortex beams based on all-dielectric metasurfaces

In recent years, the perfect vortex beam with independent wavefront spiral correlation has attracted extensive attention since its beam diameter is independent of topological charge.Perfect vortex beams are expected to make significant progress in optical fiber communications, particle manipulation, quantum information, and other areas.Traditional optical devices are difficult to integrate into the system due to their large size.In this paper, we design and realize a perfect vortex beam with a high reflection efficiency of 90.17% by an all-dielectric metasurface through a Pancharatnam-Berry (PB) phase modulation structure.The cross-polarization conversion efficiency measured by experiment is 89.81%.By modulating the parameter r 0 in the phase function, we can achieve flexible manipulation of topological charges and ring diameters.In addition, we also demonstrate the generation of a four-channel perfect vortex beam array based on the Dammann grating, with a beam uniformity of 40%.Our research will be of great significance for the realization of compact and multifunctional on-chip integrated photonic devices.