Evolution properties of the intensity distribution of an anisotropic Gaussian Schell-model beam in a turbulent atmosphere

Abstract

An analytical expression for the cross-spectral density of an anisotropic Gaussian Schell-model (AGSM) beam propagating in a turbulent atmosphere is derived, which is featured by its clear physical meaning. The evolution properties of the intensity distribution of an AGSM beam in a turbulent atmosphere are studied thoroughly. It is found that owing to the anisotropy of the source coherence, the intensity distribution can have many different evolution processes; but under the influence of the turbulent atmosphere, it will finally take on a circular shape. The effects of lowering the source coherence on the circularization speed of the intensity distribution are also investigated. It is found that, when the anisotropy of the source coherence is taken into account, lowering the source coherence can accelerate or decelerate the circularization of the intensity distribution. We propose and demonstrate five kinds of conditions, and, under each condition, lowering the source coherence has a unique and definite effect on the circularization speed of the intensity distribution. In particular, we give an analysis about the equivalence between the problem studied in one of our five conditions and that in the work of Cai and He [Appl. Phys. Lett. 89, 041117 (2006)] and show that their relevant conclusion is incorrect.