Efficient energy propagation through self-assembled gold nanoparticle chain waveguides

TL;DR

This paper demonstrates that gold nanoparticle chains assembled via DNA origami can efficiently guide energy at the nanoscale despite gold's inherent losses, enabling potential applications in quantum optics and sensing.

Contribution

It introduces a novel self-assembly method for gold nanoparticle chains that achieve efficient waveguiding through lower-energy plasmon modes.

Findings

Nanometer-resolution characterization confirms energy propagation.

Directed energy transfer to nanodiamonds demonstrated.

Propagation lengths potentially extend to micrometers.

Abstract

The strong interaction of light with metallic nanoparticles enables field confinement well below the diffraction limit. Plasmonic waveguides consisting of metal nanoparticle chains could be used for the propagation of energy or information on the nanoscale, but high losses have thus far impeded practical applications. Here we demonstrate that efficient waveguiding is possible through gold nanoparticle chains despite the high dissipative losses of gold. A DNA origami directed self-assembly of monocrystalline, spherical nanoparticles allows the interparticle spacing to be decreased to 2 nm or below, which gives rise to lower-energy plasmon resonance modes. Our simulations imply that these lower energy modes allow efficient waveguiding but collapse if interparticle gap sizes are increased. Individual waveguides are characterized with nanometer-resolution by electron energy loss spectroscopy, and directed propagation of energy towards a fluorescent nanodiamond and nanoscale energy conversion is shown by cathodoluminescence imaging spectroscopy on a single-device level. With this approach, micrometer-long propagation lengths might be achieved, enabling applications in information technology, sensing and quantum optics.