High-quality vector vortex arrays by holographic and geometric phase control

Abstract

Cylindrical vector vortex (CVV) beams are topical forms of structured light, and have been studied extensively as single beams, non-separable in two degrees of freedom: spatial mode and polarisation. Here we create arrays of CVV beams using a combination of dynamic phase controlled Dammann gratings and spin-orbit coupling through azimuthally varying geometric phase. We demonstrate control over the number, geometry and vectorness of the CVV arrays by simple adjustment of waveplates and computer generated holograms. To quantify the efficacy of our approach, we employ a recently proposed vector quality factor analysis, realising high quality vector beam arrays with purities in excess of 95%. Our approach is scalable in array size, robust (no interferometric beam combination) and allows for the on-demand creation of arbitrary vector beam arrays, crucial for applications that require multi-spot arrays, for example, in fast laser materials processing, multi-channel communication with spatial modes, and holographic optical traps, as well as in fundamental studies with vector optical lattices.