Polarizing properties of a 2D photonic crystal slab for simultaneous in-plane and out-of-plane light incidence

We study a 2D photonic crystal slab for its properties of polarizing light propagating in the plane of periodicity and for light incident from outside the plane of the slab as well. We identify the frequency ranges that can yield polarized light for both cases. The analysis is done for triangular and square lattice configurations in both symmetric and asymmetric background media. The 2D photonic crystal slab can behave as both reflection-type and transmission-type polarizer for in-plane and out-of-plane incidence of light. The structure in an asymmetric background, which is more favorable for practical applications, yields orthogonally polarized out-of-plane transmitted states which ultimately radiate to the cladding medium within certain frequency interval of the incident light.