Study On The Quality Of Partial Coherent Beam Passing Through Non - Kolmogorov Atmospheric Turbulence Beam

The beam quality of laser beams in atmospheric turbulence play a very important role in laser communication, optical radar and space exploration applications, thus causing long-term concern to researchers. The research work provides experimental basis and theoretical model for the application of space optical communication in practice. This paper mainly studies the propagation characteristics of laser beams propagating through non-Kolmogorov atmospheric turbulence, the main research contents are as follows:1. Based on the non-Kolmogorov spectrum, using the extended Huygens-Fresnel principle and the definition of second-order moments of the Wigner distribution function(WDF), the analytical expressions for the propagation factors of partially coherent Hermite-Gaussian(H-G) beams propagating through non-Kolmogorov atmospheric turbulence are derived, and used to study the influence of non-Kolmogorov atmospheric turbulence on the propagation factors of partially coherent H-G beams. It is shown that the smaller the propagation distances, the outer scale, the general structure constant, the spatial coherence length, and the larger the inner scale, the beam orders, the less the propagation of partially coherent H-G beams is affected by non-Kolmogorov atmospheric turbulence, the better the beam quality. When the general exponent is 3.11, the beam quality of partially coherent H-G beams is the poorest through atmospheric turbulence.2. The analytical expressions for the kurtosis parameters and strehl ratio of first-order(the topological charge m=?1) Gaussian Schell-model(GSM) vortex beams and non-vortex beams propagating through non-Kolmogorov atmospheric turbulence are derived. According to the expressions of kurtosis parameters can be obtained, The outer scale and the generalized structure constant is larger, the smaller the inner scale, the beam profile is more sharp, among them affected by the generalized structure constant is maximum. In addition, the kurtosis parameters of the vortex beams increases with the propagation distances, instead of the kurtosis parameters of the non-vortex beams remains constant, beam profile is not influenced by turbulence. According to the expression of strehl ratio can be obtained, the outer scale and the generalized structure constant are smaller, the inner scale bigger, the strehl ratio will be higher, the beam quality is better. In addition, non-vortex beam is more easily affected by turbulence than vortex beams.3. The analytical expressions for the propagation factors and angular spreads of high-order(the topological charge m?1) Gaussian Schell-model(GSM) vortex beams and non-vortex beams propagating through non-Kolmogorov atmospheric turbulence are derived. According to the expressions of propagation factors can be obtained, the smaller the outer scale, the general structure constant, and the larger the inner scale, the topological charges, the less the propagation of partially coherent H-G beams is affected by non-Kolmogorov atmospheric turbulence, the better the beam quality. When the general exponent is 3.11, the beam quality is the poorest. According to the expressions of angular spreads can be obtained, the smaller the outer scale, the general structure constant, and the larger the inner scale, the topological charge, the angular spread is smaller, the beam quality is better.