Measurement of the Probability Distribution of Total Transmission in Random Waveguides

Measurements have been made of the probability distribution of total transmission of microwave radiation in waveguides filled with randomly positioned scatterers which would have values of the dimensionless conductance $g$ near unity. The distributions are markedly non-Gaussian and have exponential tails. The measured distributions are accurately described by diagrammatic and random matrix calculations carried out for nonabsorbing samples in the limit $g\gg 1$ when $g$ is expressed in terms of the variance of the distribution, which equals the degree of long-range intensity correlation across the output face of the sample.