Theoretical insights into charge transfer plasmon lifetime

TL;DR

This paper provides a classical electromagnetism-based theoretical analysis of charge transfer plasmon resonances in conductively connected gold nanodisk dimers, revealing their longer lifetime and potential for optical computing applications.

Contribution

It introduces a detailed theoretical model to describe the spectral and temporal dynamics of charge transfer plasmons, including their lifetime and phase behavior, which was not previously characterized.

Findings

Charge transfer plasmons have longer lifetimes than particle and dimer plasmons.

The lifetime of charge transfer plasmons can be extended by geometric manipulation.

Charge transfer modes oscillate out of phase with other plasmon modes.

Abstract

Understanding the spectral and temporal dynamics of charge transfer plasmon resonances that emerge in conductively connected plasmonic nanoparticles is crucial for exploiting their potentials for enhanced infrared spectroscopy and optical computing. In this article, we present a theoretical study based on classical electromagnetism to describe the spectral signature and dephasing time of charge transfer plasmons. By fitting the scattering curves and near-field amplitude oscillations, we determine the spectral linewidth and lifetime of charge transfer plasmons in conductively connected gold nanodisk dimers. We find that, compared with the well-known particle plasmons and dimer plasmons, charge transfer plasmons have a longer lifetime, which can be further extended by manipulating the geometric parameters of nanojunction and nanoparticles. Moreover, quantitative analyses of the optical near-field amplitude reveal that charge transfer plasmon modes oscillate completely out of phase with particle plasmon and dimer plasmon modes. The dephasing time and charge transfer rate are found to be on a few femtosecond timescale, implying that conductively connected plasmonic nanoparticles hold great promise as channels for coherent transfer of energy and information in future all-optical computing devices.