Magneto-optical characteristics of symmetric and asymmetric spin photonic crystals

The transmission properties of one-dimensional (1-D) symmetric spin photonic crystals (SPCs), consisting of dielectric SiO2 and magnetic bismuth-substituted YIG multilayers, were investigated. The perfectly periodic structures yield the same transmittance spectra, regardless of the order of the layers. The order of the layers in the SPCs, including defect layers, influences the transfer characteristics. More magnetic defect layers bring about a broader width of photonic bandgap and a larger transmittance at the defect modes compared to the dielectric ones, while more dielectric defects give rise to a considerable Faraday rotation. The reflection properties of 1-D SPCs with three-defect asymmetric structures were also studied. The results reveal that only forty-four layers in this asymmetric configuration are required for an enhanced Kerr rotation of about 45 degrees with a high reflectance of >= 95%, due to the increased degrees of freedom. More importantly, these conditions are met at both normal and slightly oblique incidence.