Measuring geometric phase without interferometry

TL;DR

This paper introduces a straightforward non-interferometric method to measure the geometric phase of structured Gaussian beams by analyzing intensity distributions after mode transformations, linking optical trajectories to geometric phase changes.

Contribution

It presents a novel approach to measure geometric phases without interferometry, utilizing intensity distributions and mode transformations, and reveals an optical analogue of Ehrenfest's theorem.

Findings

Geometric phase can be determined from intensity distributions.

Trajectories of intensity centroids resemble ray optics paths.

The method links geometric phase to observable intensity patterns.

Abstract

A simple non-interferometric approach for probing the geometric phase of a structured Gaussian beam is proposed. Both the Gouy and Pancharatnam-Berry phases can be determined from the intensity distribution following a mode transformation if a part of the beam is covered at the initial plane. Moreover, the trajectories described by the centroid of the resulting intensity distributions following these transformations resemble those of ray optics, revealing an optical analogue of Ehrenfest's theorem associated with changes in geometric phase.