Quantum Dynamics of Plasmonic Coupling in Silver Nanoparticle Dimers: Enhanced Energy and Population Transfer via Emitter Interaction

Plasmonic nanoparticles (NPs), characterized by significant localized surface plasmon excitations, can generate exceptionally large electromagnetic fields. In the plasmonic cavity, the enhancement of population and energy transfer across closely spaced metallic NPs significantly influence the optical response of the emitter. The theoretical investigation of transport properties in plasmonic nanocavities in atomic-scale level of calculation is important to characterize the optical response of the system. We model the coupling of plasmonic excitations of silver NPs in a bowtie configuration and generate new bright and dark states according to symmetry. By varying the separation distance, the rate of population and energy transfer between two NPs are analyzed within the framework of quantum dynamics multiconfiguration time-dependent Hartree (MCTDH) algorithm. The coupling of the emitter with bright and dark states of the plasmonic cavity is investigated based on the dipole-dipole approximation. The Hermitian Hamiltonian parametrized with first-principles calculations is applied to model the whole system. These results can reveal a connection between atomistic properties and optical response in the subnanometric-scale.