Statistical measurements of irradiance fluctuations of a multipass laser beam propagated through laboratory-simulated atmospheric turbulence

Experimental results are presented for the statistics of 0.6328-μm laser irradiance fluctuations for multiple-pass propagation through a laboratory-simulated atmospheric turbulence of strength $C_n^2=2.476\times {10}^{-11}{\text{m}}^{-2/3}$ and the smallest scale size l₀ = 2.74 mm. The coefficients of variation γ₀, skewness γ₁, and excess γ₂ of irradiance fluctuations are plotted as a function of path length. From the plots of γ₂ vs γ₁ for various values of ${\sigma }_1^2(=1.23k^{7/6}{C}_n^2{L}^{11/6})$ in different regions within the turbulence, the following forms of the probability distribution functions for the irradiance fluctuations are considered: lognormal, Rice-Nakagami, m distribution, gamma (and exponential), and K distribution. We have also demonstrated the characteristic feature of −8/3 power law behavior of power spectrum and the shift of Tatarski's peak frequency in the case of strong turbulence.