Plasmonic responses of metallic/dielectric core-shell nanoparticles on a dielectric substrate

Abstract

The effect of material selection on the plasmonic response and local absorption are evaluated for core- shell nanoparticles placed over a BK7 glass substrate. Eight different core-shell pairs are studied using the vectorized version of discrete dipole approximation with surface interactions (DDA-SI). Two classes of dielectric core-metallic shell and metallic core-dielectric shell particles are considered. It is shown that core-shell structures with dielectric materials can have absorption enhancement compared to the bare metallic nanoparticles. Moreover, it is observed that core-shell pairs yield multipeak localized surface plasmon resonance (LSPR) response due to their hybrid structure. Absorption enhancement and LSPR tuning ranges are shown with different dielectric materials that can be used in localized heating of designated core-shell NPs placed over a surface for nanomanufacturing purposes. In order to determine the optimum size configurations, a number of core-shell pairs are explored with specified volumetric filling ratio of core materials.