ABSTRACT
Plasmon-based optical antennas featuring a nanometer-sized gap can enhance the photophysical properties of solid-state quantum emitters by several orders of magnitude at room temperature. However, controlling the position and orientation of an isolated emitter in a metallic resonator, at the nanometer scale, has only been achieved in scanning probe geometries. Using radially polarized cylindrical vector beams and DNA-assembled gold nanoparticle dimers, we demonstrate the reproducible interaction of single dye molecules with the bright longitudinal mode of a plasmonic cavity, achieving decay rate enhancements of 2 orders of magnitude. These results demonstrate that interfacing efficiently isolated quantum emitters and optical nanoantennas is possible on a large scale.
ABSTRACT
An aureate dye: Confined electromagnetic fields in DNA-templated gold nanoparticle dimers were tuned to engineer the fluorescence properties of organic dyes in water (see picture). Purified suspensions of hybrid metal-organic chromophores featured unprecedented photophysical properties, such as a short lifetime and low quantum yield but high brightness.
Subject(s)
Fluorescent Dyes/chemistry , Gold/chemistry , Optics and Photonics , Organogold Compounds/chemistry , DNA/chemistry , Diffusion , Dimerization , SolubilityABSTRACT
A photon interacts efficiently with an atom when its frequency corresponds exactly to the energy between two eigenstates. But at the nanoscale, homogeneous and inhomogeneous broadenings strongly hinder the ability of solid-state systems to absorb, scatter or emit light. By compensating the impedance mismatch between visible wavelengths and nanometre-sized objects, optical antennas can enhance light-matter interactions over a broad frequency range. Here we use a DNA template to introduce a single dye molecule in gold particle dimers that act as antennas for light with spontaneous emission rates enhanced by up to two orders of magnitude and single photon emission statistics. Quantitative agreement between measured rate enhancements and theoretical calculations indicate a nanometre control over the emitter-particle position while 10 billion copies of the target geometry are synthesized in parallel. Optical antennas can thus tune efficiently the photo-physical properties of nano-objects by precisely engineering their electromagnetic environment.
Subject(s)
DNA/chemistry , Nanostructures/chemistry , Nanotechnology/methods , Photons , Bioengineering/methods , Coloring Agents/chemistryABSTRACT
We demonstrate that symmetric or asymmetric gold nanoparticle dimers with substantial scattering cross sections and plasmon coupling can be produced with a perfectly controlled chemical environment and a high purity using a single DNA linker as short as 7 nm. A statistical analysis of the optical properties and morphology of single dimers is performed using darkfield and cryo-electron microscopies. These results, correlated to Mie theory calculations, indicate that the particle dimers are stretched in water by electrostatic interactions.
