Polarization microstatistics of laser speckle

The microstatistics of laser speckle has been investigated under varying incident polarization angle {θ}. The intensity at each point in a speckle pattern varies sinusoidally with {θ} and can be described completely by three parameters: amplitude, baseline, and relative phase. The probability-density distributions for these parameters were obtained by carefully measuring the intensity modulation in several thousand independent coherence areas. Samples were studied which spanned the full range of depolarization ratio {ρ}, recently suggested to be the main parameter needed to describe microstatistics. Excellent agreement with recent theoretical results for unity {ρ} was observed in the amplitude microstatistics. For different samples having the same value of {ρ}, differences were seen for the baseline microstatistics at low value, possibly suggesting a need to include other light-scattering parameters in the description of the microstatistics. Furthermore, the decay of the baseline microstatistics measured at high values is not in good agreement with theoretical predictions. Finally, the distributions obtained for high {ρ} values for speckle in transmission show excellent agreement with those in reflection.