Diffraction-induced magneto-optical enhancement in gyrotropic gratings

The spectra of diffracted magneto-optical Kerr effect (D-MOKE), for polar magnetization in one- dimensional gyrotropic gratings, were presented by Antos \textit{et al.} [Appl. Phys. Lett. \textbf{86}, 231101 (2005)]. It was noted that the magnitude of Kerr rotation in the first-order diffraction was one order higher than that of the zeroth-order diffraction in most of the energy range. In this study, a rigorous coupled-wave approach, implemented as Airy-like internal series, was applied to investigate the diffraction-induced MO enhancement. The simulated spectra of D-MOKE are consistent with their experimental ones. Moreover, it was found that the magnitude ratio of the first-order Kerr rotation to the zeroth-order one was strongly dependent on the grating depth. In other words, D-MOKE can be effectively modulated by the groove depth. This theoretical approach is of great significance in designing and applying the diffracted MO elements.