Spatially resolved enhancement of fluorescence and Raman scattering by Ag nanoparticle arrays

TL;DR

This paper demonstrates how ordered silver nanoparticle arrays can significantly enhance fluorescence and Raman signals of nearby molecules through surface plasmon resonances, with spatially resolved imaging revealing localized effects.

Contribution

It introduces a method to fabricate ordered silver nanoparticle arrays that enhance optical signals and provides spatially resolved imaging of these effects at the nanoscale.

Findings

Fluorescence decay rate increased by an order of magnitude near nanoparticles.

Fluorescence emission intensity was significantly enhanced.

Raman scattering was amplified by over 5 orders of magnitude.

Abstract

Highly ordered periodic arrays of silver nanoparticles have been fabricated which exhibit surface plasmon resonances in the visible spectrum. We demonstrate the ability of these structures to alter the fluorescence properties of vicinal dye molecules by providing an additional radiative decay channel. Using fluorescence lifetime imaging microscopy, we have created high resolution spatial maps of the molecular lifetime components; these show an order of magnitude increase in decay rate from a localized volume around the nanoparticles, resulting in a commensurate enhancement in the fluorescence emission intensity. Spatial maps of the Raman scattering signal from molecules on the nanoparticles shows an enhancement of more than 5 orders of magnitude.