PARIS, Aug. 1, 2012 — A bio-inspired light nanoantenna has been created using two gold nanoparticles, short DNA strands and a tiny fluorescent molecule that can capture and emit light. The discovery paves the way toward the development of highly efficient LEDs and ultracompact solar cells and could even find use in quantum cryptography.
Light is a wave, so it should be possible to develop optical antennas that can amplify light signals in the same way that televisions and mobile phones capture radio waves. However, because light oscillates a million times faster than radio waves, nanoscale objects are needed to capture the very fast lightwaves. Therefore, the optical counterpart of a basic antenna (of dipole type) is a quantum emitter that is surrounded by two nanoparticles a thousand times smaller than a human hair.
Schematic representation of a nanoantenna formed of two gold nanoparticles linked by a DNA double strand and supplied by a single quantum emitter. (Image: ©Busson, Rolly, Stout, Bonod, Bidault)
Scientists at CNRS and Aix Marseille Université created the simple, user-friendly optical antenna by embedding a fluorescent organic colorant and 36-nm-diameter gold particles into short artificial DNA strands. The fluorescent molecules behave like a quantum source, providing photons to the antenna, while the interaction between the light and the emitter is amplified by the gold nanoparticles. They produced in parallel several billion replicas of these particle pairs (in solution) via control of the fluorescent molecule positions with nanometric accuracy because of the DNA backbone.
These features extend beyond the possibilities offered by existing lithography techniques used to design microprocessors.
The study appeared in the July 17 issue of Nature Communications
For more information, visit: www.cnrs.fr/paris-michel-ange