Angular momentum redirection phase of vector beams in a non-planar geometry

TL;DR

This paper explores how non-planar propagation induces geometric phases in scalar and vector light fields, causing rotation of polarization and intensity profiles proportional to the sum of topological charge and helicity.

Contribution

It demonstrates that polarisation and intensity profiles rotate together in non-planar paths, with the geometric phase depending on the sum of topological charge and helicity, and identifies eigenmodes unaffected by the path.

Findings

Polarization and intensity profiles rotate by the same angle in non-planar propagation.

The geometric phase is proportional to j=l+sigma.

Radial and azimuthally polarized beams with j=0 are eigenmodes unaffected by the path.

Abstract

An electric field propagating along a non-planar path can acquire geometric phases. Previously, geometric phases have been linked to spin redirection and independently to spatial mode transformation, resulting in the rotation of polarisation and intensity profiles, respectively. We investigate the non-planar propagation of scalar and vector light fields and demonstrate that polarisation and intensity profiles rotate by the same angle. The geometric phase acquired is proportional to j=l+sigma, where l is the topological charge and sigma is the helicity. Radial and azimuthally polarised beams with j= 0 are eigenmodes of the system and are not affected by the geometric path. The effects considered here are relevant for systems relying on photonic spin Hall effects, polarisation and vector microscopy, as well as topological optics in communication systems