Generation of optical vortex light beams by volume holograms with embedded phase singularity

TL;DR

This paper theoretically analyzes how volume holographic elements with embedded phase singularities can generate optical vortex beams, showing that their thickness influences beam quality and enabling symmetric vortex formation.

Contribution

It introduces a theoretical model for OV beam generation by volume holograms with embedded phase singularities, highlighting the impact of hologram thickness on beam properties.

Findings

Hologram thickness affects OV beam selectivity and efficiency.

The model predicts the possibility of symmetric OV beams regardless of diffraction angle.

Numerical analysis confirms the influence of volume hologram structure on beam evolution.

Abstract

Special features of the optical-vortex (OV) beams generated by thick holographic elements (HE) with embedded phase singularity are considered theoretically. The volume HE structure is based on the 3D pattern of interference between an OV beam and a standard reference wave with regular wavefront. The incident beam diffraction is described within the framework of a linear single-scattering model in which the volume HE is represented by a set of parallel thin layers with the "fork" holographic structure. An explicit integral expression is derived for the complex amplitude distribution of the diffracted paraxial beam with OV. The numerical analysis demonstrates that the HE thickness may essentially influence not only selectivity and efficiency of the OV beam generation but also the amplitude and phase profile of the diffracted beam as well as regularities of its propagation. We have studied the generated OV morphology and laws of its evolution; in particular, the possibility of obtaining a circularly symmetric OV beam regardless of the diffraction angle is revealed.