Transverse Momentum Exchange in Optical Vector Beam Propagation: Theory and Experiment

TL;DR

This paper introduces a theoretical model and experimental validation for transverse momentum exchange in optical vector beams, revealing how polarization gradients influence beam acceleration during propagation.

Contribution

It presents a novel model predicting momentum exchange due to polarization gradients and experimentally demonstrates beam acceleration caused by this effect.

Findings

Observation of beam centroid following a parabolic path

Validation of the momentum exchange model

Identification of polarization gradient effects on beam dynamics

Abstract

In this work we present a model for the paraxial propagation of vector beams. Of particular importance is the appearance of a new transverse momentum term proportional to the linear polarization angle gradient imparted to the beam during the beam preparation process. The model predicts that during propagation, this new momentum will be exchanged for classical transverse momentum, thereby causing the beam to accelerate. We observe the momentum exchange in experiment by designing the polarization profile in such a way as to cause the beam centroid to follow a parabolic path through free space.