Spatial field distributions in the transition from ballistic to diffusive transport in randomly corrugated waveguides

A detailed analysis of the statistical properties of the transmitted field in corrugated waveguides in the transition from ballistic to diffusion tran sport is presented. The field distributions are found to be highly dependen t on the incident mode excited. When the speckle contrast is one, our resul ts agree with recent experiments where the intensity distribution follows t he predictions of the random-phasor-sum model, even though the field phase is not uniformly distributed. Clear deviations from the Gaussian statistics are found which can be interpreted in terms of "K" distributions arising e ither from a small number of scatterers or from perturbations of the speckl e pattern on propagation.