Spatial and temporal distributions of atmospheric refractive-index structure parameter measured by moiré deflectometry

Abstract

Random fluctuation of refractive index distorts the wavefront of light propagation in the atmosphere, which destroys the coherence of the light waves, as well as has an impact on optical detection and communication, etc. In this paper, a phase-based measurement method for synchronously temporal and spatial distributions of atmospheric refractive-index structure parameter is applied. First of all, the depended relation between phase and refractive-index structure parameter is established, based on which an experiment is adopted. In experiment, 3600 frames of moiré fringes were obtained within an hour. And then, the phase and deflection angles distributions of moiré fringes are obtained by Fourier analysis and multi-grid method. Finally, the temporal and spatial distributions of refractive-index structure parameter are yielded according to the deduced theoretical relationship. The results show that both the temporal and spatial distributions refractive-index structure parameter could be measured by moiré deflectometry, and they are in good agreement with the existing methods. In a word, the related results could provide some references for studying the refractive-index structure parameter and the influence of atmosphere on optical detection and communication.