Influence of atmospheric absorption in the inner optical system on the laser beam quality

The power in the bucket(PIB),β parameter,astigmatic parameter,Strehl ratio and the center of beam gravity are reguarded as the characteristic parameters of the laser beam quality in the far field,the influence of absorption in the inner optical system on the laser beam quality is studied.Results are compared with and without the presence of the transversal wind.By using a four-dimension simulation code,a large number of numerical calculations are performed and the results are analyzed physically.It is shown that the peak intensity and focus ability of laser beams increase with decreasing absorption coefficient and increasing wind velocity.However the transversal wind results in an astigmatism.