Kaihara Terunori, Ando Takeaki, Shimizu Hiromasa, Zayets Vadym, Saito Hidekazu, Ando Koji, Yuasa Shinji
Opt Express. 2015 May 4;23(9):11537-55. doi: 10.1364/OE.23.011537.
Giant enhancement of the magneto-optical Kerr effect (MOKE) by surface plasmon polaritons (SPPs) is theoretically shown in a trilayer structure consisting of double-layer dielectrics and a ferromagnetic metal (Al2O3/SiO2/Fe). We calculated the resonant enhancement of the transverse MOKE (TMOKE) and polar MOKE (PMOKE) using the attenuated total reflection (ATR) configuration with the transfer matrix method using a 4 × 4 scattering matrix. At a specific film thickness of the low-index SiO2 layer, where confinement of the SPPs on the Fe surface becomes close to the cutoff condition, the incident light from the Al2O3 couples with the SPPs at the SiO2/Fe boundary most efficiently, resulting in resonant enhancement of the MOKE at an incident angle corresponding to the wave vector of the SPPs. The calculated PMOKE showed orthogonal transformation (90°-rotation) and almost full-orbed deformation (44°-ellipticity) of the polarization, and the TMOKE showed a change in reflectance of about 34 dB upon magnetization reversal.
理论上表明，在由双层电介质和铁磁金属（Al2O3/SiO2/Fe）组成的三层结构中，表面等离激元极化激元（SPP）可使磁光克尔效应（MOKE）大幅增强。我们使用4×4散射矩阵的传输矩阵法，通过衰减全反射（ATR）配置计算了横向MOKE（TMOKE）和极化MOKE（PMOKE）的共振增强。在低折射率SiO2层的特定膜厚下，当Fe表面上的SPP限制接近截止条件时，来自Al2O3的入射光与SiO2/Fe边界处的SPP最有效地耦合，从而在与SPP波矢对应的入射角处导致MOKE的共振增强。计算得到的PMOKE显示出极化的正交变换（90°旋转）和几乎完全的椭圆变形（44°椭圆率），而TMOKE在磁化反转时显示出约34 dB的反射率变化。
