１次元磁性フォトニック結晶の局在モードの磁気光学性能指数

Abstract

Magneto-optical (MO) figure-of-merit parameters of localized modes in one-dimensional magnetophotonic crystals (1D-MPC) with bismuth-substituted yttrium iron garnet (Bi:YIG) film were studied numerically by using the matrix approach based on the 4 × 4 matrix formalism. The structure of 1D-MPC is expressed as (SiO2/SiN)R/Bi:YIG/(SiN/SiO2)R with the stacking number R, where the Bi:YIG interlayer acts as a defect supporting the magneto-optically active localized modes. The study revealed that the localized modes exhibit large figure-of-merit parameters with very thin Bi:YIG layers; for instance, when R = 10 and dM (Bi:YIG thickness) = 0.15 μm, the first localized mode at λ ≈ 650 nm exhibits T (transmissivity) ≈ 50% and θF (Faraday rotation) = -6 deg., resulting in a figure-of-merit of QF = T1/2|θF| ≈ 4 deg. for the Faraday operation, while the localized mode shows R (reflectivity) ≈ 8% and θK (Kerr rotation)=16 deg., yielding QK=R1/2|θK| ≈ 4.5 for the Kerr operation. These results strongly indicate that the 1D-MPC structure is very effective for realizing large figure-of-merit parameters (comparable to those of Bi:YIG bulk materials) by using very thin Bi:YIG layers.