Nano Letters paper published online

21 Janvier 2011 , Rédigé par JW Publié dans #Recent research work

Our study on fluorescence enhancement and beaming in nanoapertures with circular corrugations has just been released on the Nano Letters website. See the abstract here. A free reprint (for personal use only) can be downloaded here

Rationale: A wide range of applications in physical and chemical sciences is presently limited by the weak optical signal emitted by a single fluorescent molecule. To overcome this challenge, plasmonic antennas are receiving a growing interest to control both the fluorescence rate and angular emission distribution from single quantum emitters. However, there is currently no experimental demonstration reporting a clear improvement in both the emission intensity and directionality using the same nanoantenna. We solve this issue here.

Results: we report the demonstration of bright unidirectional photon sources from single molecules. The emission rate per molecule is enhanced up to 120 fold, and simultaneously the fluorescence emission is directed into a narrow angular cone of 15°. This work has four major aspects of general interest:

1) Each of our results on enhancing the fluorescence signal and narrowing the angular distribution is going well beyond the current state-of-the-art, and moreover, we achieve both features simultaneously on the same structure, which is unique to our knowledge.

2) Nanoapertures surrounded by periodic corrugations have generated a considerable interest in the photonics community. This is the first study where corrugated apertures are used to enhance the detection of single molecules.

3) We thoroughly quantify the increased light-matter coupling and the radiation pattern at the single emitter level.

4) The bright emission and narrow directionality release the need for high-end microscope objectives. Efficient detection of single molecules is achieved with a simple low numerical aperture objective.