Research on the influence of random refractive index medium on wave front detection in long optical path

The random distribution of refractive index caused by air turbulence is an important factor affecting the accuracy of optical measurement, especially in the field of precision measurement. At present, the analysis of the influence of random refractive index medium on wave front detection in long optical system is based on practical experiments. In this paper, based on the existing ray tracing methods and image quality evaluation criteria in the medium with variable refractive index, the ray tracing is performed on the medium with long optical path with the random refractive index distribution, and the relevant influence characteristics are measured and studied. First, a set of normally distributed atmospheric density data with a constant mean value and variance are generated and the corresponding refractive index data is obtained which includes dry air density and water vapor density in the current environment. Then, the ray tracing is carried out in the random medium and uniform medium respectively. Two kinds of image quality evaluation criteria, PV and RMS, are obtained by comparing the simulation results. Through simulation, the influence of random distribution of media on optical testing results can be measured, and the post-processing of test data can be guided. The simulation results show that the larger the variance of the normal distribution of atmospheric density is, the more serious the wave front distortion is. The methods proposed in this paper can be applied to optical testing fields such as interference measurement.