Cavity enhancement simulation of the magneto-optical Kerr effect in optically anisotropic multilayer structure

In this work, a quadrilayer optical cavity of SnO2/Co/SnO2/Al/Si was established to investigate the Kerr rotations enhancement of the optically anisotropic Co film. Using the boundary matrix and the transmission matrix, the Kerr rotations of the multilayer cavity were provided. Simulation results showed that, at the incident wavelength of 300 nm, Kerr rotations in polar and longitudinal geometry could be obtained as 8.45 degrees and 0.735 degrees, respectively, which were much larger than that of the single optically anisotropic film. In addition, the Kerr rotation could be modulated by controlling the cavity length to fulfill the phase matching. After that, the optimized interlayer SnO2 thickness and incident angle were calculated as 40 nm and 30 degrees in the cavity. Simulation results confirmed that this method could effectively enhance the Kerr rotations of the optically anisotropic Co film.