Dynamics, effciency and energy distribution of nonlinear plasmon-assisted generation of hot carriers

TL;DR

This study investigates how surface plasmons in gold antennas influence the nonlinear generation, energy distribution, and relaxation dynamics of hot carriers, with implications for optimizing plasmonic devices.

Contribution

It demonstrates the nonlinear formation of hot carriers via surface plasmons and quantifies their dynamics and absorption cross-section in optical gold antennas.

Findings

Carrier relaxation time ranges from 500 fs to 2.5 ps

Surface plasmons enable nonlinear hot carrier generation

Quantitative analysis of absorption cross-section

Abstract

We employ nonlinear autocorrelation measurements to investigate plasmon-assisted hot carrier dynamics generated in optical gold antennas. We demonstrate that surface plasmons enable a nonlinear formation of hot carriers, providing thus a unique lever to optimize the energy distribution and generation efficiency of the photo-excited charges. The temporal response of the carriers' relaxation can be controlled within a range extending from 500~fs to 2.5~ps. By conducting a quantitative analysis of the dynamics, we determine the nonlinear absorption cross-section of individual optical antennas. As such, this work provides strong insights on the understanding of plasmon-induced hot carrier generation, especially in the view of applications where the time response plays a preponderant role.