Spin–orbit conversion-enabled generation of cylindrical vector beams

Abstract

Taking advantage of the significant spin-to-orbital angular momentum conversion (SOC) that happens at the nonparaxial focus, we present a novel approach to generate radial, azimuthal and hybrid polarized cylindrical vector beams (CVBs) of different orders. Retroreflecting the normal and SOC anomalous beams, present simultaneously at the nonparaxial focus, results in their in situ, on-axis, and axisymmetric superposition leading to the generation of polarization-structured light beams. Theoretical simulation of the generated beams’ characteristics matching with experimental measurements and representation of the generated beams on a higher-order Poincaré sphere provide a deeper understanding and manipulation of the complex polarization structures within tightly focused beams. The direct measurement of spatially structured transverse, longitudinal, and total angular momenta and energy flows in the focal region of the generated higher-order CVBs are expected to open up novel experimental possibilities.