Radially engineered metasurface for the generation of a perfect higher-order Poincaré beam

Perfect higher-order Poincaré beams (HPBs) trigger various applications such as particle trapping and super-resolution imaging due to the space-variant polarization. The generation of perfect HPBs necessitates the intricate phase superposition of conjugated perfect vortex beams (PVBs), while achieving high-efficiency cross-polarization transmission via the same-sized nanopatterns remains challenging. In this work, we introduce a radially engineered metasurface (REM) enabling perfect HPB generation with 99.3% cross-polarization transmission and 100% polarization conversion efficiency through the same-sized metasurface. The geometric phase of the REM is engineered by combining a radial regulation phase (RRP) and spiral phase profiles, enabling the generation of conjugated cross-polarized PVBs with opposite topological charges under circularly polarized light illumination. Precise arrangement of nanocylindroids at calculated radial positions facilitates polarization state manipulation, producing anisotropic perfect HPBs under incident linear polarization light, whose polarization evolution from radial to azimuthal configurations is visualized on the Poincaré sphere. The REM further exhibits double-channeled orbital angular momentum multiplexing for holography via a modified Gerchberg–Saxton algorithm. Our findings show great potentials in dynamic generation and precise manipulation of HPBs, offering applications in integrated optical communication devices and meta-holography.