Experimental Simulation Of Adaptive Correction Of Wave-front Distortion For Atmospheric Transmission Of High Power Laser

During the transmission of high power laser in the atmosphere,the beam quality will be seriously reduced due to the effect of atmospheric turbulence and thermal blooming.Adaptive optics can effectively improve the performance through wave-front phase compensation in optical system.Traditional adaptive optics system is mainly aimed at the wave-front correction of atmospheric turbulence effect.Since thermal blooming belongs to the nonlinear effects,high power laser has higher tolerance requirements for adaptive optics system.The research on wave-front detection and compensation has large difference compared with the traditional adaptive optics.Under the natural environment,high power laser adaptive research has problems of uncontrolled conditions and high experimental cost.It is of great significance to carry out experimental simulation and adaptive correction of high power laser transmission at atmosphere in the laboratory.With the theory on effects of atmospheric turbulence and thermal blooming in high power laser transmission,laser transmission light field is evaluated by multi-phase screen simulation to analyze the weak fluctuation turbulence under Kolmogorov spectrum and steady-state thermal blooming.Besides,it gives a discription on phase distortion due to the influence of turbulence with different intensity and thermal blooming with different thermal distortion parameters.This provides theoretical support for experimental simulation on the effects of turbulence and thermal blooming in laboratory condition.Moreover,it is helpful for the design and construction of adaptive optical correction closed-loop system.The steady-state thermal blooming effect in the coherent length of 0.013?0.100m and the thermal distortion parameter in the range of 5?50 can be experimentally simulated by using the hot air turbulence simulator and Spatial Light Modulator(SLM),respectively.In addition,a closed-loop adaptive correction system is carried out with experiments,utilizing wave-front sensor,deformable mirror and supporting professional control software.Based on the light wave scalar diffraction theory,the formula of SLM loading phase on light field is derived under steady thermal blooming.Besides,it improves the phase error caused by the way that the phase of thermal blooming light field is directly loaded into SLM to generate simulated light field.Finally,it enhances the effect of SLM simulation on thermal blooming.Wavefront aberration corrected by adaptive optics system of high-power laser facility in atmospheric transmission is built.Besides,the correction ability of call number in different drive systems is analyzed.For instance,when the call number is 20,the correction effect has been more than 70%.However,when the call number is too high,due to the introduction of noise,the correction effect falls down.The best of correction effect can reach more than 85%.A high power laser transmission system with simple equipment and a comprehensive simulation experiment method of adaptive optics correction in laboratory is presented.Finally,realize the adaptive correction of high power laser transmission in the atmosphere under laboratory environment.