Analysis of the dispersion of speckle polarization on the Poincaré sphere

Abstract

A polarimeter using the Stokes - Mueller formalism has been adapted to analyse speckle polarization. The noise effects on the Mueller matrix are minimized to separate the experimental noises from the depolarization phenomenon. The polarization of speckle grains changes with the angle of incidence whereas the global depolarization of the target is increased. As a part of the depolarization results from a mixing of polarization, the polarization dispersion of the speckle grains on the Poincaré sphere is analysed by using the polarization barycentre as a parameter. It appears that the polarization dispersion increases with the angle of incidence. In order to simplify this depolarization phenomenon, we have studied a polished iron sample.