Experimental Study of Vortex Laser Radiation Propagation in a Turbulent Atmosphere

The use of vortex laser radiation can significantly increase the information capacity of data transmission channels in free-space optical communication systems. However, atmospheric turbulence substantially limits the application of such systems. This work analyzes the experimental study of the influence of different atmospheric turbulence conditions on vortex laser radiation characteristics. Vortex fields were generated using a phase light modulator; initial distributions of vortex beam intensity were represented by sets of concentric rings. An increase in the topological charge increased the number of those rings and reduced their thickness. It was found that, despite equal initial beam sizes, the diffractive beam size increased with the topological charge by the end of a 500-meter atmospheric propagation path, thus reducing random wandering of the beam energy centroid. As the topological charge increases, the relative turbulence-induced broadening also decreases, and the scintillation level rises. No dependence was found between the beam topological charge and the radius of the spatial correlation of turbulent intensity fluctuations. The experimental results supplement existing knowledge about the propagation of vortex laser radiation in a turbulent atmosphere and can be used in the design of free-space optical communication systems.