Engineered polar magneto-optical Kerr rotation through Wood–Rayleigh anomalies and magnetoplamon resonance coupling

Abstract

Polar magneto-optical Kerr rotation (MOKR) is an important phenomenon in magneto-optical materials. Both intensive and narrow Kerr rotation spectra are needed to ensure the high performance of magneto-optical devices. In this work, by using a nanosphere template and Ag film deposition at different angles, glass/Cr/Ag/Fe/PSS/Ag samples with different Ag nanostructures between polystyrene spheres were fabricated, and different optical modes and their coupling were manipulated. Polar MOKR peaks were demonstrated and analyzed. Narrow and intensive polar MOKR peaks were presented with the Ag film deposited at a glancing angle θ = 30°. The physical mechanism was studied by simulating the electromagnetic-field distribution. It was found that, in the glass/Cr/Ag/Fe/PSS/Ag system with the Ag film deposited at different angles, different optical modes and their interaction are introduced. Polar MOKR peaks due to the coupling between Fabry–Perot and Bragg plasmons was broad. However, polar MOKR spectra governed by the coupling of WRA and magnetoplasmons demonstrated intensive and narrow peaks for samples with the Ag film deposited at θ = 30°, which would improve the performance of magneto-optical devices with high sensitivity, compact volume, high-density data storage devices, and so on.