The spatial degree of polarization and the first-order statistical properties of polarization speckle

In analogy with the degree of polarization used widely for the description of partially polarized thermal light, we introduced a new concept of the spatial degree of polarization to characterize the statistical properties of the polarization speckle with its polarization states fluctuating in space. As a function of the spatial degree of polarization, the first order statistics of the polarization speckle are studied theoretically, and the corresponding probability density functions of the Stokes parameters are measured experimentally by a polarization interferometer to demonstrate the validity of the principle.