Key points are not available for this paper at this time.
We report the first full numerical analysis of polarization gratings (PGs), and study their most general properties and limits by using the finite-difference time-domain (FDTD) method. In this way, we avoid limiting assumptions on material properties or grating dimensions (e. g. , no paraxial approximations) and provide a more complete understanding of PG diffraction behavior. We identify the fundamental delineation between diffraction regimes (thin versus thick) for anisotropic gratings and determine the conditions for 100% diffraction efficiency in the framework of the coupled-wave and Q parameters. Diffraction characteristics including the efficiency, spectral response, and polarization sensitivity are investigated for the two primary types of PGs with linear and circular birefringence. The angular response and finite-grating behavior (i. e. , pixelation) are also examined. Comparisons with previous analytic approximations, where applicable, show good agreement.
Oh et al. (Fri,) studied this question.