Abstract:
We study the direction- and wavelength-dependent polarization anisotropy in light scattering at the air–photonic
crystal interface as a function of angle of incidence for TE and TM polarized light. This is done using optical
reflectivity measurements at high-symmetry points in the Brillouin zone of a three-dimensional photonic crystal
with fcc symmetry. Polarized reflectivity measurements indicate the presence of stop gap branching for TE
polarization, which is absent for TM polarization until the Brewster angle at the K point. In contrast, stop
gap branching is present for both TE and TM polarizations at the W point due to the intricate mixing of crystal
planes. This characteristic behavior signifies the inevitable role of energy exchange in the stop gap branching. The
measured polarization anisotropy shows a prominent shift in the Brewster angle for the on-resonance wavelength
as compared to the off-resonance along both K and W points, and that is in accordance with theory. Our results
have implications in polarization-induced light scattering in subwavelength photonic structures such as plasmonic
crystals, and metamaterials.
