Influence of Spatial Dispersion in Metals on the Optical Characteristics of Bimetallic Plasmonic Nanoparticles

The problem of diffraction of a plane electromagnetic wave field from a layered nanoparticle, composed of two plasmonic metals, is considered. The influence of spatial dispersion in metals on the absorption cross section has been investigated based on the method of discrete sources. Different combinations of core and shell metals (Au@Ag and Ag@Au) for spheroidal particles are studied, and the influence of elongation and asymmetry of the particle geometry on the energy absorption is investigated. It is established that consideration of the spatial dispersion both in the core and the shell leads to a significant decrease in the absorption cross section and a shift of the plasmon resonance to shorter wavelengths.