Interplay between generic and mesoscopic speckle statistics in transmission through random media

We explore the interplay between generic and mesoscopic aspects of speckle patterns appearing in a single polarization component of the transmitted field of multiply scattering media. The crucial role of phase singularities in speckle patterns of diffusing and localized microwave radiation in quasi-one-dimensional samples is demonstrated in the dynamics of local transmission, in the statistics of structural features within the speckle pattern and in the motion of singularities as the frequency is scanned. We also describe a crossover between one- and three-dimensional propagation in random layered media with transverse disorder associated with an optical delocalization transition. The transition occurs at the thickness beyond which singularities are formed in the transmitted speckle pattern as the transverse spread of the wave becomes larger than the field correlation length. These studies demonstrate the relationship between field structures within individual Gaussian speckle patterns and non-ergodic statistics of local and integrated transmission for diffusive and localized waves in ensembles of random samples.