Mapping Nanoscale Hotspots with Single-Molecule Emitters Assembled into Plasmonic Nanocavities Using DNA Origami

Research output: Contribution to journalArticle

Authors

  • Rohit Chikkaraddy
  • V. A. Turek
  • Nuttawut Kongsuwan
  • Felix Benz
  • Cloudy Carnegie
  • Tim Van De Goor
  • Bart De Nijs
  • Ortwin Hess
  • Ulrich F. Keyser
  • Jeremy J. Baumberg

Colleges, School and Institutes

External organisations

  • University of Cambridge
  • Imperial College London

Abstract

Fabricating nanocavities in which optically active single quantum emitters are precisely positioned is crucial for building nanophotonic devices. Here we show that self-assembly based on robust DNA-origami constructs can precisely position single molecules laterally within sub-5 nm gaps between plasmonic substrates that support intense optical confinement. By placing single-molecules at the center of a nanocavity, we show modification of the plasmon cavity resonance before and after bleaching the chromophore and obtain enhancements of ≥4 × 103 with high quantum yield (≥50%). By varying the lateral position of the molecule in the gap, we directly map the spatial profile of the local density of optical states with a resolution of ±1.5 nm. Our approach introduces a straightforward noninvasive way to measure and quantify confined optical modes on the nanoscale.

Details

Original languageEnglish
Pages (from-to)405-411
JournalNano Letters
Volume18
Issue number1
Early online date22 Nov 2017
Publication statusPublished - 10 Jan 2018

Keywords

  • DNA origami , nanoassembly , nanocavities , plasmonics , Purcell factor , SERS , single-molecule , strong coupling