Theoretical analysis of optical and magneto-optical properties of one-dimensional magnetophotonic crystals

We present a procedure for analyzing the properties of multilayer structures with magnetic film. The magneto-optical effect in multilayer-structure magnetic films [e.g., bismuth-substituted yttrium iron garnet (YIG)] and dielectric films (e.g., SiO2 and Ta2O5) was investigated theoretically and experimentally to examine the correlation between the magneto-optical properties and the localization effect of light. The film structure of interest, which has symmetric periodicity, is the (Ta2O5/SiO2)n/Bi:YIG/(SiO2/Ta2O5)n structure, where n is the repetition number. We fabricated experimentally a one-dimensional magnetophotonic crystal film of (Ta2O5/SiO2)n/Bi:YIG/(SiO2/Ta2O5)n (n=2,6) structures. The theoretical calculation and the measured value for the Faraday rotation were in close agreement. Furthermore, the Faraday rotation of the multilayer structure with n=6 is 150 times larger than that of a Bi:YIG single-layer film. This is of interest from the point of view of actual magneto-optical device (e.g., optical isolator) fabrication.