Watching a Single Fluorophore Molecule Walk into a Plasmonic Hotspot

TL;DR

This paper presents a DNA origami-based nanosystem enabling a single fluorophore molecule to autonomously walk into a plasmonic hotspot, allowing real-time observation of enhanced light-matter interactions at the nanoscale.

Contribution

It introduces a novel dynamic platform where a single molecule can precisely and autonomously enter a plasmonic hotspot, advancing control over quantum emitter positioning.

Findings

Fluorescence intensity increases as the molecule approaches the hotspot.

Fluorescence lifetime decreases during the approach.

Successful demonstration of autonomous molecular walking into a plasmonic hotspot.

Abstract

Plasmonic nanoantennas allow for enhancing the spontaneous emission, altering the emission polarization, and shaping the radiation pattern of quantum emitters. A critical challenge for the experimental realizations is positioning a single emitter into the hotspot of a plasmonic antenna with nanoscale accuracy. We demonstrate a dynamic light-matter interaction nanosystem enabled by the DNA origami technique. A single fluorophore molecule can autonomously and unidirectionally walk into the hotspot of a plasmonic nanoantenna along a designated origami track. Successive fluorescence intensity increase and lifetime reduction are in situ monitored using single-molecule fluorescence spectroscopy, while the fluorophore walker gradually approaches and eventually enters the plasmonic hotspot. Our scheme offers a dynamic platform, which can be used to develop functional materials, investigate intriguing light-matter interaction phenomena, and serve as prototype system for examining theoretical models.