斜程大气传输激光束的平均光强与短期光束扩展

基于广义惠更斯-菲涅耳原理、修正von Karman 湍谱、贝塞耳权重函数的高斯函数近似和误差小于4%的波结构函数平方近似，研究得出了包含湍流尺度影响的湍流大气中传输高斯光束的平均光强新关系和包含湍流外尺度影响的光束短期扩展因子。研究了高斯光束等效半径与传输距离、初始光束束径和光波波长间的关系，结果表明，在给定折射率结构参量和传输距离情况下，存在极小短期光束扩展对应的特征初始束径和特征光波波长。

Average intensity and short-term beam spread of a laser beam propagating in a slant-path atmosphere

Based on the extended Huygens-Fresnel principle, the modified von Karman spectrum for refractive-index fluctuations，Gaussian approximation for the product of Gaussian function with Bessel function and a quadratic approximation of the structure function of wave, within an error ≤4%, new expressions are derived for the mean irradiance and the short-term beam spread of a Gaussian beam propagating in slant path turbulent atmosphere which include the effects of atmosphere- turbulence scale. The effective radius of the Gaussian beam depending on the beam propagation distance, initial beam size and wavelength are studied. The results show that the short-term beam spread has a distinctive minimum at a certain optimum initial beam size, when the beam propagation length, the refractive index structure parameter and the wavelength of optical beam are given.