A universal model is proposed for the irradiance fluctuations of an optical beam propagating through atmospheric turbulence. When this model was compared with existing measured data, we found good qualitative and quantitative agreement, which suggests that this new theoretical model is applicable under all known conditions of turbulence. In the regime of weak scattering, the normalized moments of the distribution are essentially the same as those predicted by the lognormal model, although they show large deviations from lognormal statistics in the saturation regime. The limiting form of the universal model for conditions of super-strong turbulence is that of the negative-exponential distribution, but, for more moderate conditions of turbulence, the form is that of an exponential times an infinite series of Laguerre polynomials. The new distribution was derived under the assumption that the field irradiance consists of two principal components, each of which has an amplitude that is <i>m</i> distributed.
© 1982 Optical Society of AmericaPDF Article