Imaging of plasmonic modes of silver nanoparticles using high-resolution cathodoluminescence spectroscopy

TL;DR

This study uses high-resolution cathodoluminescence spectroscopy and simulations to analyze plasmonic modes in silver nanoparticles, revealing detailed spatial and spectral characteristics of their resonant modes.

Contribution

It provides a combined experimental and numerical approach to image and understand plasmonic modes in silver nanoparticles at nanometer resolution.

Findings

Electron beam excites out-of-plane eigenmodes in silver nanoparticles.

Spatial field variation of resonant modes resolved below 25nm.

Simulation results agree well with experimental cathodoluminescence data.

Abstract

Cathodoluminescence spectroscopy has been performed on silver nanoparticles in a scanning electron microscopy setup. Peaks appearing in the visible range for particles fabricated on silicon substrate are shown to arrive from excitation of out of plane eigenmodes by the electron beam. Monochromatic emission maps have been shown to resolve spatial field variation of resonant plasmon mode on length scale smaller than 25nm. Finite-difference time-domain numerical simulations are performed for both the cases of light excitation and electron excitation. The results of radiative emission under electron excitation show an excellent agreement with experiments. A complete vectorial description of induced field is given, which complements the information obtained from experiments.