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  Nonlinear Time-Frequency Analysis of Laser Beam  Intensity Fluctuations


T. I. Arsenyan, M. I. Babanina, N. A. Soukhareva, A. P. Sukhorukov

 M.V.Lomonosov's Moscow State University, Physics Faculty


Received July 26, 2013


Abstract. Nonlinear time-frequency analysis was applied to the intensity fluctuations of a laser beam propagated  through the model turbulent path.  For this purpose the Wigner-Ville mapping of  intensity distributions  and their first four spatial moments were used. The characteristics of time-frequency maps corresponding  to different modes of propagation channel are discussed as well as anisotropy and temporal scales  of intensity fluctuations. The experiments on the model path  revealed astigmatic distortions of the beam caused by the wind load and thermal lens defocussing.

Keywords: turbulent media, Wigner-Ville mapping, laser beam distortions, astigmatic distortions, FSO.