Abstract

Light beams carrying both spin (polarization) and orbital angular momentum (OAM) can be represented by mapping the total angular momentum onto a higher-order Poincaré sphere [1]. Due to the non-separability of the polarization and OAM degrees-of-freedom, these beams, commonly known as vector vortex beams, find varieties of applications in scientific and technological fields including photon entanglement [2], material processing [3] and microscopy [4]. Such beams are commonly generated using q-plates [5] and liquid crystal based spatial light modulators [6]. However, the limitation of low power handling and restricted wavelength coverage of such techniques can be addressed through the vector vortex beam generation using nonlinear parametric processes. Unfortunately, the dependence of phase-matching of the parametric processes on the polarization of the interacting beams puts the major hindrance to the nonlinear generation of vector vortex beams. Here we report a novel experimental scheme to generate vector vortex beams using single pass second harmonic generation (SHG) of ultrafast higher order vector vortex beams.

© 2019 IEEE