Ring dislocation of the coherence degree of a vortex Bessel beam in a turbulent atmosphere

Abstract

Results of the theoretical consideration of the behavior of the coherence degree of a vortex Bessel optical beam propagating in a turbulent randomly inhomogeneous medium are presented. The influence of an optical vortex on the coherence degree of a Bessel beam in a randomly inhomogeneous medium is studied. The analysis of the problem is based on the solution of the equation for the second order mutual coherence function of the optical beam field. Based on this solution, the behavior of the absolute value of the second order mutual coherence function (coherence degree) of the vortex Bessel beam field is studied. It is shown that a ring dislocation the number of rings in which is equal to the value of the topological charge of the optical beam, forms in the central part of the two-dimensional field of the coherence degree of vortex Bessel beams at low levels of fluctuations in a turbulent atmosphere. The structure of the ring dislocation of the coherence degree of vortex Bessel optical beams in a turbulent atmosphere is studied in detail. For this purpose, two characteristics of the ring dislocation are introduced: its spatial coordinate and ring width. The influence of parameters of an optical beam (transverse wavenumber and topological charge) and atmospheric turbulence (coherence radius of a plane optical wave) on these characteristics of the ring dislocation of the coherence degree of a vortex Bessel optical beam is considered.