Abstract

The statistics of the intensity fluctuations of light that has propagated through atmospheric turbulence are described as the product of an optical field that obeys Rice-Nakagami statistics and a lognormal modulation factor. The probability density function that results contains two parameters: the coherence parameter of the Rice-Nakagami field and the variance of the logarithm of the modulation factor. If it is assumed that turbulent scales less than the Fresnel zone size contribute to the loss of coherence of the wave and that turbulent scales greater than this size contribute to the random modulation, both parameters can be calculated from physical parameters such as turbulence strength, inner scale, optical wavelength, and path length. In very weak path-integrated turbulence, the probability density function described here is very nearly lognormal, in agreement with the data. A scaling constant in the parameter calculation is chosen so that the intensity variance in this limit is that predicted by the first-order Rytov theory. In very strong turbulence, this density asymptotically approaches a negative exponential, in agreement with a number of theoretical predictions.

© 1986 Optical Society of America