Optical And Rf Beam Propagation In Turbulent Media

The optical beam spread and the optical beam quality factor in the presence of both an initial quartic phase aberration and atmospheric turbulence is analyzed. We obtain analytical expressions for both the mean-square beam radius and the beam quality factor using the moment method. We compare these expressions to the results from Monte Carlo simulations, which allows us to mutually validate the theory and the Monte Carlo simulation codes. We also discuss the reason for the discrepancy between the moment method and the classical approach for calculating the ensemble-averaged mean-square beam radius in a turbulent atmosphere that is described by Andrews and Phillips and by Fante.