Drastic Reduction of Plasmon Damping in Gold Nanorods

TLDR

Light‑scattering spectroscopy on individual gold nanoparticles was used to study plasmon dephasing. Gold nanorods exhibit a markedly lower plasmon dephasing rate than nanospheres because interband damping is suppressed, and their small volumes minimize radiation damping, leading to strong local‑field enhancement and high scattering efficiencies, while pure dephasing and interface damping are negligible.

Abstract

The dephasing of particle plasmons is investigated using light-scattering spectroscopy on individual gold nanoparticles. We find a drastic reduction of the plasmon dephasing rate in nanorods as compared to small nanospheres due to a suppression of interband damping. The rods studied here also show very little radiation damping, due to their small volumes. These findings imply large local-field enhancement factors and relatively high light-scattering efficiencies, making metal nanorods extremely interesting for optical applications. Comparison with theory shows that pure dephasing and interface damping give negligible contributions to the total plasmon dephasing rate.