General scattering characteristics of resonant core-shell spheres

We present the general features and aspects regarding the electromagnetic scattering by a small core-shell sphere. First, the thickness effects on the plasmonic resonances are described in the Rayleigh limit, utilizing the MacLaurin expansion of the Mie coefficients of hollow scatterers. The results are connected with the plasmon hybridization model. A brief study regarding the core effects is given, illustrating resonant scattering peculiarities. Finally, new electrodynamic aspects of the scattering process are revealed through a the newly introduced Padé expansion of the Mie coefficients. The proposed methods can be readily applied for the studies of the dynamical dependencies for other canonical shapes, carving ways for engineering the overall properties of a single composite scatterer.