Influence of turbulent atmosphere on the effect of coherent beam combining

Coherent beam combining is a promising technology for achieving a high-power laser beam with good beam quality. However, turbulent atmosphere is one of the key factors that restrict its application and development. This paper focuses on the influence of atmospheric Greenwood frequency on the correction effect of the coherent combination system based on Stochastic Parallel Gradient Descent (SPGD) algorithm. At first, the influence of different turbulence intensities on the correction effect of coherent combination systems is analyzed by numerical simulation under static atmospheric conditions. Then, a set of rotating phase screens that meet Kolmogorov's statistical law are generated by numerical calculation to simulate the turbulent atmosphere and study the correction effect of coherent combination system at different atmospheric Greenwood frequencies. Finally, an experimental platform is established to demonstrate the coherent combination effect of two laser beams. The simulated and experimental results show that when the system's control algorithm iteration frequency (350 Hz) is constant, the disturbance of turbulent atmosphere to the phase and light intensity of laser beams will increase with atmospheric Greenwood frequency, making the effect of coherent combination worse.