Research on the influence of air turbulence of vertical long optical path on wave front detection

Indoor air turbulence had a certain degree of influence on optical testing or optical system image quality. A long optical testing path was built in tower which was one of the largest vertical towers for optical testing in China with about 23-meter high. The relevant influence characteristics were measured and studied in a specific state. First, the air turbulence was formed using air conditionings. Then, the optical wave fronts were sampled by interferometer with two conditions of undisturbed situation and disturbed situation in which the air conditioners were turned on for a while and then turned off some time and sampling was beginning. After the statistical analyzing to the sampling results, the following several evaluation results of image quality were acquired in different status, the Radius of Encircled 80% Energy (REE), the evaluation factor of modulation transfer function (MTF), the Strehl Ratio (SR), the traditional evaluation method PV/RMS value of wave fronts, and the turbulent correlation length of atmospheric r0. The statistical calculation results showed that turbulence intensity increased and optical image quality was deteriorated after air disturbed.