Spatio-Temporal Scintillation Mitigation via Polarizations Coupled Higher-Order Correlation

TL;DR

This paper develops a theoretical framework linking polarization and higher-order correlations to reduce scintillation in free-space optical communication through atmospheric turbulence.

Contribution

It introduces a unified model connecting polarization, higher-order correlations, and scintillation, and demonstrates how polarization control can mitigate scintillation independently of turbulence strength.

Findings

Polarization control reduces scintillation independently of turbulence.

A closed-form purity relation links polarization matrices to scintillation.

Experimental results confirm the effectiveness of combined coherence and polarization control.

Abstract

We present a unified theoretical framework linking second and fourth order statistical correlations of stochastic electromagnetic beams to the scintillation index observed after propagation through Kolmogorov atmospheric turbulence. We derive the beam coherence polarization matrix and its propagation law in a random medium. An algebraic connection is established between the second order polarization matrix J, its fourth order Gram counterpart obtained from the square of J, the classical degree of polarization P, the fourth order degree of polarization, and the scintillation index of the beam intensity. A key result is a closed form purity relation connecting the trace of the squared polarization matrix to the square of its trace, which shows that unpolarized natural beams exhibit a large scintillation index. The analysis demonstrates that scintillation can be reduced by polarizing the beam using suitable polarizer sets. This reduction occurs independently of the atmospheric turbulence strength parameter. Experimental results further show that simultaneous control of coherence and polarization, achievable using a pseudo random phase plate, provides a practical approach for minimizing scintillation in free space optical communication links.