Plasmonics Effects of Nanometal Embedded in a Dielectric Substrate

We numerically report on first realization of near-field interaction and localized surface Plasmon resonance of a pair of silver-shell nanospheres with different dielectric holes embedded in a dielectric substrate using finite element method. An electromagnetic mode different from the solid case of the same volume is excited inside and outside the shell surface, resulting in an intensity enhancement in a gap of particle pair surrounding the particle-substrate interface. We find that the embedded depth of the nanoparticles pair in a substrate will influence the position of the localized fields which is confined in the gap. Besides, the near-field intensity becomes less intense and the spectrum of peak resonances red-shifted as the index difference of interface and embedded depth decreases. The proposed models have been prepared to cover the ultraviolet-visible, visible, and near-infrared (NIR) regions with application to sensors and spectroscopy purposes by varying the embedded depth and pertinent to the functionality of sensors, spectroscopy, and other optical devices.