The influence of turbulence on propagation properties of partially coherent sinh-Gaussian beams and their beam quality in the far field

摘要

Based on the extended Huygens-Fresnel principle, the closed-form propagation equation of partially coherent Sinh-Gaussian (ShG) beams through the turbulent atmosphere has been derived by using the quadratic approximation of the Rytov's phase structure function. The influence of turbulence on propagation properties of partially coherent ShG beams and their beam quality in the far field are studied both analytically and numerical. The fully coherent ShG beam has been treated as a special case of the partially coherent ShG beam when the degree of spatial coherence a = infinity. It is shown that in comparison with the free-space propagation the turbulence accelerates the evolution of three stages that partially coherent ShG beams undergo. The smaller alpha is, the less partially coherent ShG beams are affected by the turbulence. In particular, we find that the beta parameter decreases as the decentered parameter delta increases, but the dependence of the Strehl ratio on delta is not monotonous. There exists an optimal delta(opt,) the influence of turbulence on the maximum intensity of the corresponding partially coherent ShG beam with delta(opt) is the smallest. Therefore, a suitable choice of 6 may reduce the influence of turbulence on the beam quality in the far field in practice. (c) 2007 Elsevier Ltd. All rights reserved.