Effect of atmospheric turbulence on propagation properties of optical vortices formed by using coherent laser beam arrays

TL;DR

This paper analytically investigates how atmospheric turbulence affects the propagation of optical vortices generated by coherent laser arrays, revealing conditions for vortex preservation and decoherence effects.

Contribution

It derives a propagation formula for laser arrays in turbulent atmosphere and analyzes the impact on vortex formation and stability, which was not previously detailed.

Findings

Turbulence can prevent vortex formation or cause vortex disappearance.

Higher topological charge vortices propagate longer distances in moderate turbulence.

Long-distance propagation leads to loss of vortex property and transition to Gaussian beams.

Abstract

In this paper, we consider the effect of the atmospheric turbulence on the propagation of optical vertex formed from the radial coherent laser beam array, with the initially well-defined phase distribution. The propagation formula of the radial coherent laser array passing through the turbulent atmosphere is analytically derived by using the extended Huygens-Fresnel diffraction integral. Based on the derived formula, the effect of the atmospheric turbulence on the propagation properties of such laser arrays has been studied in great detail. Our main results show that the atmospheric turbulence may result in the prohibition of the formation of the optical vortex or the disappearance of the formed optical vortex, which are very different from that in the free space. The formed optical vortex with the higher topological charge may propagate over a much longer distance in the moderate or weak turbulent atmosphere. After the sufficient long-distance atmospheric propagation, all the output beams (even with initially different phase distributions) finally lose the vortex property and gradually become the Gaussian-shaped beams, and in this case the output beams actually become incoherent light fields due to the decoherence effect of the turbulent atmosphere.