Watching a Single Fluorophore Molecule Walk into a Plasmonic Hotspot

Abstract

Plasmonic nanoantennas allow for enhancing the spontaneous emission, altering\nthe emission polarization, and shaping the radiation pattern of quantum\nemitters. A critical challenge for the experimental realizations is positioning\na single emitter into the hotspot of a plasmonic antenna with nanoscale\naccuracy. We demonstrate a dynamic light-matter interaction nanosystem enabled\nby the DNA origami technique. A single fluorophore molecule can autonomously\nand unidirectionally walk into the hotspot of a plasmonic nanoantenna along a\ndesignated origami track. Successive fluorescence intensity increase and\nlifetime reduction are in situ monitored using single-molecule fluorescence\nspectroscopy, while the fluorophore walker gradually approaches and eventually\nenters the plasmonic hotspot. Our scheme offers a dynamic platform, which can\nbe used to develop functional materials, investigate intriguing light-matter\ninteraction phenomena, and serve as prototype system for examining theoretical\nmodels.\n