Linear polarization rotation in multilayer topological insulator structures

Abstract

The linear polarization conversion effect of reflected electromagnetic wave from topological insulator (TI) multilayer structure is investigated. We calculate the reflection coefficients of the anisotropic TI multilayer structure based on the transfer matrix method, and the polarization conversion effect is characterized by the polarization conversion rate and Kerr rotation angle. Polarization conversion at each interface in the TI multilayer with parallel magnetization on TI surfaces can be accumulated, and the complete polarization conversion may occur in the structure consisting of sufficiently many TI layers. The polarization conversion rate is lowered with increasing frequency and exhibits significant oscillation behavior with frequency as the layer thickness increases. Fewer TI layers are required to obtain complete polarization conversion for the structure with larger topological admittance parameter, and the rotation effect of polarization is suppressed by increasing the incidence angle. The out-of-plane uniaxial anisotropy of the TI may also affect the polarization conversion in the TI multilayer.