Measurement of Pancharatnam's phase by robust interferometric and polarimetric methods

TL;DR

This paper presents robust interferometric and polarimetric methods for measuring Pancharatnam's phase in polarization states of light, demonstrating theoretical and experimental results that are resilient to disturbances and applicable to various interferometer types.

Contribution

The authors introduce a robust interferometric approach that can measure Pancharatnam's phase across the full Poincaré sphere, applicable to multiple interferometer configurations and extendable to mixed states.

Findings

Interferometric array is resistant to mechanical and thermal disturbances.

Polarimetric and interferometric methods yield results consistent with theory.

Versatile approach applicable to different interferometer types.

Abstract

We report theoretical calculations and experimental observations of Pancharatnam's phase originating from arbitrary SU(2) transformations applied to polarization states of light. We have implemented polarimetric and interferometric methods which allow us to cover the full Poincar\'e sphere. As a distinctive feature, our interferometric array is robust against mechanical and thermal disturbances, showing that the polarimetric method is not inherently superior to the interferometric one, as previously assumed. Our strategy effectively amounts to feed an interferometer with two copropagating beams that are orthogonally polarized with respect to each other. It can be applied to different types of standard arrays, like a Michelson, a Sagnac, or a Mach-Zehnder interferometer. We exhibit the versatility of our arrangement by performing measurements of Pancharatnam's phases and fringe visibilities that closely fit the theoretical predictions. Our approach can be easily extended to deal with mixed states and to study decoherence effects.