Nonlocal Response of Plasmonic Nanostructures Excited by Dipole Emitters

The interaction between light and plasmonic structures at the deep-nanometer scale, which is essentially governed by nonclassical effects, has been increasingly investigated by the hydrodynamic model. Several hydrodynamic models have been introduced, in order to describe the motion of the free electron gas in metals. In this work, by employing the hard wall hydrodynamic model (HW-HDM) and the quantum hydrodynamic model (Q-HDM), the nonlocal response of an isolated metallic nanoparticle, excited by a dipole emitter, is investigated. The analysis is performed for the local density of states of an emitter coupled with a spherical nanoparticle, which may be treated analytically. Both radial and tangential emitters are studied, while varying the emitter–nanoparticle separation, and the nanoparticle’s size and material. It is shown that HW-HDM and Q-HDM may generate striking spectral features, which do not arise within the classical approach.