Fluorescence enhancement through modified dye molecule absorption associated with the localized surface plasmon resonances of metallic dimers

Abstract

Nano-antennae consisting of gold particle dimers were fabricated by electron-beam lithography. Dark-field scattering spectroscopy was used to probe the plasmonic response of individual nano-antennae and to characterize the localized surface plasmon resonances they support. Fluorescence from dye molecules dispersed in a thin polymer film that covered the dimers was used to probe the interaction between fluorophores and the nano-antennae. Through a suitable choice of dye emission spectrum and spectral position of the dimer resonance, we were able to focus on the way the plasmon resonances may mediate absorption of incident light by the dye. We separated out the role of plasmon resonances on absorption from emission. This was done using energy transfer in a donor–acceptor pair of dyes.