Polarization based intensity correlation of polarization speckle

TL;DR

This paper introduces and investigates polarization based intensity correlation in polarization speckle, revealing its dependence on spatial average intensity and the correlation between orthogonal polarization components, with potential applications in cryptography.

Contribution

It proposes a novel polarization based intensity correlation measure and demonstrates its theoretical and experimental behavior in polarization speckle patterns.

Findings

Correlation range depends on average intensity of polarization components.

Non-zero correlation observed between orthogonally polarized speckles.

Experimental results match theoretical predictions.

Abstract

A new, different kind of intensity correlation, denoted as polarization based intensity correlation, is proposed and investigated to study the correlation between different polarization components of polarization speckle, which has non-uniform spatial polarization distribution. It is shown both theoretically and experimentally that the range of the polarization based intensity correlation for a particular polarization component of the polarization speckle depends on the spatial average intensity of the speckles corresponding to that particular polarization component. The experimentally determined nature of the change of range of the intensity correlation for different polarization components, due to variation in the average intensity, is found to be matching well with the theoretical prediction. The existence of non-zero correlation between two orthogonally polarized speckle patterns, filtered from a partially depolarized speckle pattern, is also observed. This study may be useful in exploiting the polarization based intensity correlation for different applications such as speckle cryptography etc.