Zero-mode waveguide metal nanoapertures are receiving a large interest owing to their ability to confine light at the nanoscale and enhance the fluorescence emission from single molecules. However, the interest for more advanced geometries beyond the vanilla circular shape remains badly understood.
In a recent publication in Nanoscale Advances, introduce a rational design for rectangular nanoapertures, and demonstrate how this optimized shape outperforms the classical circular zero-mode waveguides both in the visible and in the deep UV.
- Rectangular nanoapertures provide 50% brighter photon count rates together with shorter lifetimes as compared to their circular counterparts.
- We derive clear design parameters related to physical concepts.
- We achieve the highest fluorescence enhancement reported so far for deep UV plasmonics.
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.