Giant enhancement of the Faraday effect in a magnetoplasmonic nanocomposite

We demonstrate a giant enhancement of the Faraday effect in a magnetoplasmonic nanocomposite based on Au nanoparticles and a bismuth-substituted iron-garnet film. The Faraday effect gets increased by more than 20 times with respect to the same bare magnetic film due to the excitation of the single and collective localized plasmon resonances in the Au nanoparticles. The phenomenon is studied for different thicknesses of the iron-garnet layer. A decrease of the iron-garnet layer thickness provides a spectral shift of the plasmonic resonances and increases the enhancement of the Faraday effect. The giant enhancement of the Faraday rotation was obtained due to an optimal ratio of parameters of plasmonic and magnetic subsystems of the composite. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement