Nanoscale control of smFRET by a scanning photonic nanoantenna

Förster Resonance Energy Transfer (FRET) governs energy exchanges at the nanoscale and can be used to accurately measure intra- and inter-molecular distances with sub-nm accuracy. While photonic nanoantennas have been shown to modify FRET, most of the earlier experiments lacked the ability to manipulate the distance between the antenna and the emitters.

In a collaboration with ICFO and INSP, scanning optical antenna probes are used to directly modulate the FRET efficiency in the near-field, and image the FRET efficiencies distributions at the nanoscale. The results, published in Nanophotonics, show that the antenna creates a local perturbation competing with the FRET acceptor, which is imaged for the first time at the single molecule level as a function of the relative position between the antenna and the FRET donor-acceptor pair.