Statistical models for intensity and phase fluctuation of laser light in a turbulent medium

The probability density function of irradiance fluctuations in a turbulent atmosphere remains an open topic of research. It is generally considered that the speckle field has an elliptical-Gaussian speckle distribution, but because of its complexity there is still no exact analytical solution. By introducing the concept of random fluctuation intensity and using an equiprobability density ellipse, exact models of the random fluctuation intensity and its phase are proposed. Through theoretical analysis and numerical simulation, it is concluded that the random fluctuation intensity and its corresponding phase are independent only under the circular-Gaussian approximation.