Research highlighted by CNRS
Molecular Nano-Headlight: turning a single molecule into a bright source of light
Looking for single molecules under the microscope. Many physical and chemical methods aim at analyzing single molecule behaviors. However, single molecule detection is a challenging task, due to the very weak amount of light that is radiated by a single molecule.
Nano-Antennas to control the emission of light. To increase and control the light emitted by a single molecule, scientists from the Fresnel Institute and the Institute of Supramolecular Science and Engineering ISIS use metal antennas of nanometer dimensions. These antennas are designed to work for light as conventional antennas work for radio waves. Both the emission intensity and direction can be controled down at the single molecule level, which realizes a major breakthrough.
The researchers use a special kind of nanoantenna made of an aperture surrounded by circular corrugations milled in a gold film. This antenna transforms a standard molecule into a bright unidirectional fluorescence source: the fluorescence intensity is enhanced up to 120 fold, and almost all the light is emitted into a narrow cone in the vertical direction.
The bright emission and narrow directionality enable the detection of single molecules with a simple microscope, and improve the effectiveness of fluorescence-based applications. This demonstration is of high relevance for the development of biochemical sensing methods, light emitting devices, and quantum information processing.