Classical light analogue of the nonlocal Aharonov-Bohm effect

TL;DR

This paper demonstrates a classical optical analogue of the nonlocal Aharonov-Bohm effect by observing a non-local geometric phase in intensity correlations of incoherent light within a Mach-Zehnder interferometer.

Contribution

It introduces the observation of a two-photon Pancharatnam phase in classical light, modulated via acousto-optic interaction, revealing nonlocal geometric phase effects in intensity correlations.

Findings

Non-local geometric phase observed in classical incoherent light

Phase modulation achieved through acousto-optic interaction

Effect observable only in intensity-intensity correlations, not in lower order correlations

Abstract

We demonstrate the existence of a non-local geometric phase in the intensity-intensity correlations of classical incoherent light, that is not seen in the lower order correlations. This two-photon Pancharatnam phase was observed and modulated in a Mach-Zehnder interferometer. Using acousto-optic interaction, independent phase noise was introduced to light in the two arms of the interferometer to create two independent incoherent classical sources from laser light. The experiment is the classical optical analogue of the multi-particle Aharonov-Bohm effect. As the trajectory of light over the Poincare sphere introduces a phase shift observable only in the intensity-intensity correlation, it provides a means of deflecting the two-photon wavefront, while having no effect on single photons.