Polarization-dependent cylindrical vector vortex beams and optical skyrmion generation using all-dielectric chiral metasurfaces

This work introduces an all-dielectric chiral metasurface capable of efficiently generating a range of cylindrical vector vortex beams (CVVBs) and complex polarization structures such as optical Stokes skyrmions. The metasurface incorporates two chiral unit cells, one responsive to left circularly polarized light and the other to right circularly polarized light, demonstrating 77% circular dichroism and 72% cross-polarization conversion efficiency. It employs the geometric phase principle to achieve precise phase modulation. This design supports multifunctionality under both circularly and linearly polarized illumination, producing vortex beams with distinct topological charges for circularly polarized light and intricate first-order CVVBs for varying linear polarization angles. Furthermore, encoding tailored phase profiles onto the metasurface's subarrays facilitates the generation of optical skyrmions, expanding its applicability. This compact metasurface enables advancements in optical communications, quantum information processing, and high-resolution imaging, contributing to next-generation photonic technologies.