Nonradiative limitations to plasmon propagation in chains of metallic nanoparticles

TL;DR

This paper analyzes how nonradiative and radiative decay processes affect plasmon propagation in metallic nanoparticle chains, providing analytical models to optimize conditions for efficient plasmonic transport.

Contribution

It introduces an analytical model that describes the transition from exponential to algebraic decay of plasmon excitation, highlighting the nonradiative origin of exponential decay.

Findings

Exponential decay of plasmon excitation is purely nonradiative.

Transition from exponential to algebraic decay depends on plasmon wavelength.

Analytical expressions for propagation length and excitation profile are provided.

Abstract

We investigate the collective plasmonic modes in a chain of metallic nanoparticles that are coupled by near-field interactions. The size- and momentum-dependent nonradiative Landau damping and radiative decay rates are calculated analytically within an open quantum system approach. These decay rates determine the excitation propagation along the chain. In particular, the behavior of the radiative decay rate as a function of the plasmon wavelength leads to a transition from an exponential decay of the collective excitation for short distances to an algebraic decay for large distances. Importantly, we show that the exponential decay is of a purely nonradiative origin. Our transparent model enables us to provide analytical expressions for the polarization-dependent plasmon excitation profile along the chain and for the associated propagation length. Our theoretical analysis constitutes an important step in the quest for the optimal conditions for plasmonic propagation in nanoparticle chains.