Directional out-coupling of light from a plasmonic nanowire-nanoparticle junction

TL;DR

This study demonstrates how a silver nanoparticle coupled with a nanowire can convert surface plasmon polaritons into directional photons and influence fluorescence emission, advancing applications in quantum plasmonics.

Contribution

The paper introduces a novel experimental method to achieve directional out-coupling of light from a plasmonic nanowire-nanoparticle junction, enabling control over photon emission directionality.

Findings

Single- and dual-directional out-coupling observed

Nanowire-nanoparticle junction influences fluorescence emission direction

Potential for directional single-photon sources and quantum plasmon circuitry

Abstract

We experimentally show how a single Ag nanoparticle (NP) coupled to an Ag nanowire (NW) can convert propagating surface plasmon polaritons to directional photons. By employing dual-excitation Fourier microscopy with spatially filtered collection-optics, we show single- and dual-directional out-coupling of light from NW-NP junction for plasmons excited through glass-substrate and air-superstrate. Furthermore, we show NW-NP junction can influence the directionality of molecular-fluorescence emission, thus functioning as an optical antenna. The results discussed herein may have implications in realizing directional single-photon sources and quantum plasmon circuitry.