Hot spot-mediated non-dissipative and ultrafast plasmon passage

TL;DR

This paper demonstrates a non-dissipative, ultrafast plasmon transfer mechanism in a triple nanoparticle system, enabling coherent energy transfer with potential applications in quantum and classical information processing.

Contribution

It introduces a novel assembly of gold and silver nanoparticles that achieves near-lossless, ultrafast plasmon coupling through hot spots, supported by classical and quantum modeling.

Findings

Strong plasmonic coupling mediated by silver island

Near-zero energy dissipation during transfer

Identification of hot spots as key mechanism

Abstract

Plasmonic nanoparticles hold great promise as photon handling elements and as channels for coherent transfer of energy and information in future all-optical computing devices. Coherent energy oscillations between two spatially separated plasmonic entities via a virtual middle state exemplify electron-based population transfer, but their realization requires precise nanoscale positioning of heterogeneous particles. Here, we show the assembly and optical analysis of a triple particle system consisting of two gold nanoparticles with an inter-spaced silver island. We observe strong plasmonic coupling between the spatially separated gold particles mediated by the connecting silver particle with almost no dissipation of energy. As the excitation energy of the silver island exceeds that of the gold particles, only quasi-occupation of the silver transfer channel is possible. We describe this effect both with exact classical electrodynamic modeling and qualitative quantum-mechanical calculations. We identify the formation of strong hot spots between all particles as the main mechanism for the loss-less coupling and thus coherent ultra-fast energy transfer between the remote partners. Our findings could prove useful for quantum gate operations, but also for classical charge and information transfer processes.