Long-wavelength electromagnetic propagation in magnetoplasmonic core-shell nanostructures

Our goal is to estimate the validity of the product rule by computing the effective permittivity and magnetic permeability of magnetoplasmonic core-shell (CS) nanostructures. We discuss the departure of the simulation from the quasistatic mean-field product rule when calculated close from resonance. The corrections to mean-field analysis are shown to be so large at a high fraction of CS inclusion that they can exceed the mean-field value by more than 750% (at the plasmon resonance). It is further shown how the spatially nonuniform electric and magnetic field enhancements extend over nanometer length scales.