Influence of atmospheric turbulence on states of light carrying orbital angular momentum

TL;DR

This paper experimentally investigates how atmospheric turbulence affects the purity of light beams carrying orbital angular momentum, revealing uniform degradation and mode cross-talk using simulated turbulence modeled by Kolmogorov theory.

Contribution

It provides the first experimental analysis of OAM mode degradation under simulated atmospheric turbulence using a phase-only spatial light modulator.

Findings

Turbulence causes uniform degradation of OAM mode purity.

Cross-talk between OAM modes increases with turbulence.

All tested modes are equally affected regardless of mode number.

Abstract

We have experimentally studied the degradation of mode purity for light beams carrying orbital angular momentum (OAM) propagating through simulated atmospheric turbulence. The turbulence is modeled as a randomly varying phase aberration, which obeys statistics postulated by Kolmogorov turbulence theory. We introduce this simulated turbulence through the use of a phase-only spatial light modulator. Once the turbulence is introduced, the degradation in mode quality results in cross-talk between OAM modes. We study this cross-talk in OAM for eleven modes, showing that turbulence uniformly degrades the purity of all the modes within this range, irrespective of mode number.