Single-Molecule Super-Resolution Microscopy Reveals How Light Couples to a Plasmonic Nanoantenna on the Nanometer Scale

Abstract

The greatly enhanced fields near metal nanoparticles have demonstrated remarkable optical properties and are promising for applications from solar energy to biosensing. However, direct experimental study of these light-matter interactions at the nanoscale has remained difficult due to the limitations of optical microscopy. Here, we use single-molecule fluorescence imaging to probe how a plasmonic nanoantenna modifies the fluorescence emission from a dipole emitter. We show that the apparent fluorophore emission position is strongly shifted upon coupling to an antenna and that the emission of dyes located up to 90 nm away is affected by this coupling. To predict this long-ranged effect, we present a framework based on a distance-dependent partial coupling of the dye emission to the antenna. Our direct interpretation of these light-matter interactions will enable more predictably optimized, designed, and controlled plasmonic devices and will permit reliable plasmon-enhanced single-molecule nanoscopy.

Advances in optoplasmonic sensors – combining optical nano/microcavities and photonic crystals with plasmonic nanostructures and nanoparticles

“…via antibodies to detect antigens). A further important consequence of the enhanced, localised fields is the several orders of magnitude increased emission and/or scattering signals from the adsorbed molecules leading to a surface-enhanced fluorescence effect and surfaceenhanced Raman scattering (SERS) [15,18,20,21]. Here, we will focus on a selection of recent developments in the synthesis of plasmonic nanostructures, fine-tuning of the electromagnetic field localisation, and enhancements at specific sites, tailored surface functionalisation, and their resulting properties.…”

Shifting molecular localization by plasmonic coupling in a single-molecule mirage

“…Interestingly, this seemingly straightforward approach does not always deliver accurate information of dye positions and electric field intensity distributions due to coupling of the emitters to localized surface plasmon resonance modes of the nanostructures. Examples include the different locations for luminescence and surface-enhanced Raman scattering (SERS) emission centres18, mismatches between nanorod dimensions determined by super-resolution imaging and atomic force microscopy21 and displaced localization of molecules close to metal nanoparticles24, nanorods2225 and nanowires19.…”

Super-resolution imaging of light–matter interactions near single semiconductor nanowires

“…Previous measurements have generally examined plasmonic properties using dye functionalized onto the surface of metallic nanostructures19202122, diffusing at low densities around a hotspot23 or immobilized in a plasmonic lattice24. These studies, however, do not map the near-field interactions away from the surface of a single structure.…”