Research on measurement of atmospheric coherence length using Shack-Hartmann wavefront sensor

Atmospheric coherence length is a very important parameter in the study of effect of atmospheric turbulence on the astronomical observation and laser propagation. Two methods of measurement of atmospheric coherence length using the Shack-Hartmann wavefront sensor are studied. One is differential image motion measure which measures the optical waves angle-of-arrival fluctuation of two subapertures. The other is to measure the wavefront distribution of stars, and the atmospheric coherence length is obtained by the residual variance of wavefront distribution. The experiment results show that the measurement results obtained by the two methods are consistent, and reliable data of atmospheric coherence length are obtained, so both methods can validate each other. The method measuring wavefront distribution and getting the current atmosphere information at the same time is achieved, and the analysis of the measurement results have reference value.