Limited Gaussian Beam Atmospheric Transmission Characteristics Analysis And Numerical Simulation Research

Laser is widely used for modern atmosphere space like atmosphere communication, laser radar, laser guidance, laser ranging, and target identification. However the using performance of the laser system is seriously damaged by the atmosphere turbulence when the laser transmitting in long distance. In practical application, laser beams usually influenced and restricted by aperture, lens and other optical component. So it is of great importance to research the laser transmitting in atmosphere turbulence.In this paper, the analytic expression of the average intensity of beams propagating through the atmosphere is possessed by the generalized Huygens-Fresnel principle and the Rytov Approximation. The influence of the aperture to the beams propagating through the atmosphere is analyzed by numerical computation and the dependence of light intensity on the propagation distance is also simulated. The changes of gauss beam getting through the lens are analyzed by using the ZEMAX software and the affection of lens on the gauss beam is restricting the beam and changing their phases. The changes of the beam getting through the aperture and lens are discussed, and the average intensity on axis is also possessed. The effect of atmosphere turbulence intensity, aperture, and wavelength on the average intensity along the axis with the different distance was simulated by the MATLAB software. The results show that the average intensity of the beam was oscillated in the near field, the extent of oscillation decreases with the increase of atmosphere and aperture, the cycle of oscillation decreases with the decreasing of distances. Oscillation is disappeared in the far field gradually with the distance increases, and the average intensity decreases smoothly. And the intensity of last maximum oscillation is inversed to the intensity of atmosphere turbulence while proportional with the aperture. At last the intensity of partially coherent flat-topped beam propagating through the turbulent atmosphere is investigated. This research provides theoretical direction for the using of gauss beam propagating in turbulent atmosphere and helpful to the application of free space optical communication and detection.