Magneto-optical control decoupled from the optical response in magnetic metallic gratings

Structured metallic and magnetic materials have attracted increasing attention due to their potential for label-free molecular detection, based on the control of the phase of light. Traditionally, tuning magneto-optical signals via magnetoplasmon leads to an excessively low light energy at the critical position in the spectrum. Thus, improving the reflectivity of magnetoplasmon-based photonic devices is a promising method to enhance their environmental adaptability. Here, we introduce a strategy for decoupling magneto-optical signal control and modulation of the reflection spectral line shape in ferromagnetic metallic gratings. This strategy is based on the sensibility of metallic gratings to the incident polarization state and the conclusion that the spin-orbit coupling induced orthogonal plasmon mode can be treated as from a pseudolight source. The decoupling and other phenomena of the oft-repeated magneto-optical Kerr rotation reversals and sensitivity to incident angle are validated using a cobalt grating.