Tailoring light emission properties of fluorophores by coupling to resonance-tuned metallic nanostructures

Abstract

We report the enhancement of the radiative decay rate of ${\mathrm{Eu}}^{3+}$ fluorophores by coupling them to nanoscopic gold disks located on a substrate. When the plasmon resonance frequency of the disks coincides with the fluorophore emission frequency, each disk acts as a supplemental antenna for the fluorophore by converting its nonradiative near field into radiating far field, thereby increasing its radiative decay rate dramatically. The radiative rate is measured by time-correlated single-photon counting for resonant and nonresonant metallic nanodisks. Supplementary theoretical model calculations are found to be in remarkably good agreement with the experiment.