Polarization-independent diffractive waveplate optics

Diffractive waveplates (DWs) generally diffract light in different directions for the two circular polarizations of light, and the diffraction efficiency of such devices generally falls when the angle through which light is diffracted becomes large. It would be desirable to be able to make fast (low f-number), high-efficiency lenses with DW type structures. We study the dependence of the efficiency of DWs and polarization volume gratings (PVGs) on the polarization and angle of incidence of light, and identify structures with polarization independent function - the diffraction efficiency and angle of diffraction. The results are obtained for DWs and PVGs periodic in one linear coordinate, however, they are applicable to other optical devices, including lenses based on these structures.