Unusual magneto-optical behavior induced by local dielectric variations under localized surface plasmon excitations

We study the effect of global and local dielectric variations on the polarization conversion r ps response of ordered nickel nanowires embedded in an alumina matrix. When considering local changes, we observe a non-monotonous behavior of the r ps , its intensity unusually modified far beyond to what it is expected for a monotonous change of the whole refractive index of the embedding medium. This is related to the local redistribution of the electromagnetic field when a localized surface plasmon is excited. This finding may be employed to develop and improve new biosensing magnetoplasmonic devices.