Effect of atmospheric turbulence on the Laguerre-Gaussian beams propagation

In order to investigate the influence of atmospheric turbulence on the vortex beams propagation quality from the perspective of free space optical (FSO) communication system, based on extended Huygens-Fresnel integral and Kolmogorov theory of atmospheric turbulence, the propagation of LG beams with different values of orbital angular momentum (OAM) in atmospheric turbulence is numerically simulated by the Fourier optics and split-Step beam propagation method. The specific diffraction model which is described by angular spectrum and the corresponding sampling conditions are given. Power in bucket (PIB) is also introduced to analyze the influence of turbulence. In addition, anti-turbulence ability is comparatively evaluated by introducing the Gaussian beam and the point light source. It is found that the atmospheric turbulence has a strong impact on the transmission properties of LG beams. With the extension of the distance, beam convergence becomes weak and diffuse, and the light intensity distribution ring and phase distribution of LG beams have suffered damage related to the OAM values. Moreover, through the comparison and analysis of PIB among several typical beams, the point light source is found to be the most sensitive to the effects of turbulence, and Gaussian beams and LG beams with smaller OAM value have similar anti-turbulence ability, furthermore, both of them outperform LG beams with larger OAM value.