Discrimination of globally unpolarized fields through Stokes vector element correlations

In a previous publication [J. Opt. Soc. Am. A 21, 988 (2004)], we examined theoretically joint probability distributions of Stokes vector elements and suggested the existence of various types of globally unpolarized light that could be discriminated through measurement of the Stokes vector element correlations. We now study the joint distribution of the degree of polarization and the three Stokes parameters as it relates to material properties in highly scattering, depolarizing random media. We describe numerical and experimental results of second-order Stokes vector element correlations, demonstrating the existence of various types of nonclassical, globally unpolarized light, and we suggest experimental means for discriminating between such field distributions. We also discuss the usefulness of the Stokes vector element correlations as an experimental tool for discriminating between different globally unpolarized fields and for verifying the assumption of Gaussian statistics usually invoked in the context of multiple light scattering.