Insights from single particle spectroscopy of plasmonic nanostructures

Abstract

A surface plasmon in a metal nanoparticle is the coherent oscillation of the conduction band electrons leading to both absorption and scattering as well as strong local electromagnetic fields. The plasmon is tunable through nanoparticel size and shape, as well as via nanoparticle interactions on different length scales that support near- and far-field coupling. Chemical synthesis and assembly of nanostructures are able to tailor plasmonic properties that are, however, typically broadened by ensemble averaging. Single particle spectroscopy together with correlated imaging is capable of removing heterogeneity in size, shape, and assembly geometry and furthermore allows one to separate absorption and scattering contributions. This talk describes how heterogeneity in crystal structure in a distribution of aluminum nanoparticles determines the damping of coherent lattice oscillations that are launched by ultrafast laser excitation.