Characterizing localized surface plasmons using electron energy-loss spectroscopy

Electron energy-loss spectroscopy (EELS) offers a window to view nanoscale properties and processes. When performed in a scanning transmission electron microscope, EELS can simultaneously render images of nanoscale objects with sub-nanometer spatial resolution and correlate them with spectroscopic information of $\sim10 - 100$ meV spectral resolution. Consequently, EELS is a near-perfect tool for understanding the optical and electronic properties of individual and few-particle plasmonic metal nanoparticles assemblies, which are significant in a wide range of fields. This review presents an overview of basic plasmonics and EELS theory and highlights several recent noteworthy experiments involving the electron-beam interrogation of plasmonic metal nanoparticle systems.