Spin-to-orbital angular momentum transfer by second harmonic generation in thin dielectric films

Abstract

We demonstrate spin-to-orbital angular momentum transfer in the bulk of nonlinear optical materials with a crystal symmetry that couples the longitudinal component of the pump field. Our predictions are exper-imentally confirmed with a thin film of gallium arsenide, which generates vortex beams of second-harmonic light when pumped with a CP Gaussian beam.