Generation and dynamics of optical beams with polarization singularities

TL;DR

This paper introduces a practical method to generate and control optical vector beams with polarization singularities using liquid crystal cells, and studies their propagation characteristics.

Contribution

A new technique for creating polarization singularity beams with adjustable L-line loops via liquid crystal cells, including analysis of their propagation behavior.

Findings

Successful generation of polarization singularity beams with controllable L-line radius

Observation of beam evolution during free-space propagation across a Rayleigh range

Demonstration of different geometrical polarization structures such as lemon, star, and spiral

Abstract

We present a convenient method to generate vector beams of light having polarization singularities on their axis, via partial spin-to-orbital angular momentum conversion in a suitably patterned liquid crystal cell. The resulting polarization patterns exhibit a C-point on the beam axis and an L-line loop around it, and may have different geometrical structures such as \qo{lemon}, \qo{star}, and \qo{spiral}. Our generation method allows us to control the radius of L-line loop around the central C-point. Moreover, we investigate the free-air propagation of these fields across a Rayleigh range.