Patent ID: 8287128

Claim:
A passive polarization diversity element for use in an imaging system to reduce speckle, the polarization diversity element comprising: a spatially and non-temporally varying polarization alteration pattern configured to alter a polarization of an homogeneously polarized incident laser beam by passively modulating portions of the incident laser beam to create a transmitted laser beam comprising diverse polarization portions, wherein the passive polarization diversity element comprises a birefringent crystal, wherein the spatially varying polarization alteration pattern comprises a spatially varying thickness of optically retarding elements across a major face of the passive polarization diversity element, wherein the spatially varying thickness of optically retarding elements is configured as a Hermite-Gaussian phase pattern varying an optical path length difference between an ordinary polarization axis and an extraordinary polarization axis of the passive polarization diversity element across the major face of the passive polarization diversity element; and a compensating element manufactured from an isotropic material configured to receive the transmitted laser beam, wherein the compensating element comprises a complementary major face to compliment the major face of the passive polarization diversity element, wherein the passive polarization diversity element and the compensating element are coupled together to form a unitary structure.