Hot electron generation through near-field excitation of plasmonic nanoresonators

TL;DR

This paper presents a theoretical study of hot electron generation via near-field excitation of plasmonic nanoresonators, demonstrating enhanced efficiency through mode excitation and strong electromagnetic confinement.

Contribution

It introduces a hybrid numerical-quantum approach to predict hot electron generation efficiency in nanoresonator setups, highlighting the role of quasinormal modes.

Findings

Strong electromagnetic field confinement at the metal surface.

Enhanced hot electron generation efficiency with nanoresonators.

Potential applications in tip-based spectroscopy and optoelectronics.

Abstract

We theoretically study hot electron generation through the emission of a dipole source coupled to a nanoresonator on a metal surface. In our hybrid approach, we solve the time-harmonic Maxwell's equations numerically and apply a quantum model to predict the efficiency of hot electron generation. Strongly confined electromagnetic fields and the strong enhancement of hot electron generation at the metal surface are predicted and are further interpreted with the theory of quasinormal modes. In the investigated nanoresonator setup, both the emitting source and the acceptor resonator are localized in the same volume, and this configuration looks promising to achieve high efficiencies of hot electron generation. By comparing with the efficiency calculated in the absence of the plasmonic nanoresonator, that is, the dipole source is located near a flat, unstructured metal surface, we show that the effective excitation of the modes of the nanoresonator boosts the generation efficiency of energetic charge carriers. The proposed scheme can be used in tip-based spectroscopies and other optoelectronic applications.