Multi-Concentric Generalized Perfect Vortex Beams by Hybrid Phase Metasurfaces

Metasurface-based vortex beams are expected to overcome the current communication challenges of massive data and limited bandwidth by their theoretical infinite and mutually orthogonal states. However, limited by the spatial extension of array vortices, only finite orbital angular momentum (OAM) eigenstates are available, of which the expansion will boost the bandwidth toward an inexhaustible stage. In this manuscript, multi-concentric generalized perfect vortex beams (G-PVBs) are experimentally generated by the fabricated hybrid phase metasurfaces integrating generalized focusing phases and circular domain function into vortex phases. Diverse vortex shapes and helical lobes within beam patterns and spiral interferograms are both arranged in a non-overlapping concentric manner instead of spatial arrays, respectively, breaking the limitation of symmetric shape while avoiding inter-modal cross-talk. The vortex shape, topological charge and vortex number are decoupled mutually in orthogonal polarization states, realizing both space and polarization multiplexing. Furthermore, shaped into anomalous profiles with asymmetric states of polarization, multi-concentric vector G-PVBs are experimentally generated to transmit parallelly stable order information with high robustness in turbulence environments. The proposed multi-concentric G-PVBs simultaneously expanded the novel vortex dimension by anomalous shapes and information channels of multi-concentric OAM modes, providing potential application in high-capacity vortex optical communication and information encryption. Multi-concentric generalized perfect vortex beams (G-PVBs) and vector G-PVBs (VG-PVBs) are experimentally generated by fabricated hybrid phase metasurfaces integrating generalized focusing phases, circular domain function into vortex phases. Vortex shapes, numbers, and topological charges are decoupled in orthogonal polarizations, realizing space and polarization multiplexing. The intensity patterns of G-PVBs and vector G-PVBs are robust and stable under experimental turbulence strength 3.1 x 10-6 m-2/3. image