Plasmonic Band Structure Controls Single-Molecule Fluorescence

Abstract

Plasmonics and photonic crystals are two complementary approaches to tailor single-emitter fluorescence, using strong local field enhancements near metals on one hand and spatially extended photonic band structure effects on the other hand. Here, we explore the emergence of spontaneous emission control by finite-sized hexagonal arrays of nanoapertures milled in gold film. We demonstrate that already small lattices enable highly directional and enhanced emission from single fluorescent molecules in the central aperture. Even for clusters just four unit cells across, the directionality is set by the plasmonic crystal band structure, as confirmed by full-wave numerical simulations. This realization of plasmonic phase array antennas driven by single quantum emitters opens a flexible toolbox to engineer fluorescence and its detection.

Directional emission from a single plasmonic scatterer

“…Rather than engineering either the driving or the structure to constrain the emitted patttern to a given asymmetric and directional distribution, we envision that the strong variability of directionality with excitation position can also be used advantageously. In particular, we propose that the type of position-dependent directionality as shown in this article lends itself perfectly for improving fluorescence correlation spectroscopy, for instance, where temporal correlations in fluorescence intensity can reveal the diffusion constant of single diffusing fluorophores 53,54 . By detecting fluorescence intensity of single molecules diffusing over the nanodisks in the Fourier plane Relative absolute magnitudes for relevant components of the multipole expansion for l 0 ¼ 400-600 nm.…”

Plasmonic phase-gradient metasurface for spontaneous emission control

“…As for antennas in the radio frequency and microwave regime, the spectral shape and polarization response of the scattered field of an antenna can be tailored by shape and orientation of the constituent particles. Antennas consisting of multiple elements can exhibit highly directional scattering properties and have been used to direct fluorescence of single local sources or ensembles of incoherently emitting sources in well-defined far-field directions [5][6][7][8][9][10]. Besides their interest for enhancing directional light emission, antennas in two-dimensional arrays have recently attracted strong interest as so-called metasurfaces.…”

Recent advances in plasmonic nanostructures for sensing: a review

“…This large range in turn results in a single MEF platform capable of being applied to a large number of different fluorophores. 159,158 Unfortunately, the directionality of the signal comes at the cost of reduced signal due to transmission through the aperture as well as restricting the optical geometry of the measurement system by making it a transmission geometry. More recently, an alternative plasmonic nanostructure with a related design, known as an "antenna in a box" [see Fig.…”