Our main current research topics are:
Cooperative scattering
When a photon is sent onto an atomic ensemble, it interacts collectively with the N atoms of the cloud and not simply with one of them. This results in measurable modifications in the scattering rate, the emission diagram or the temporal dynamics. We study these cooperative effects experimentally and theoretically. Recently, remarkable results have been obtained, in particular the direct observation of subradiance and superradiance in the linear-optics regime. This research topic is currently funded by the ANR project QuaCor and the QUANTERA project PACE-IN.
Fluctuations and correlations of light: from atoms to stars
We study the fluctuations and correlations of light after interaction with cold or hot atomic vapors, either after transmission through the atoms, or after scattering by the atoms, in the single and multiple scattering regimes. We also collaborate with astrophysicists of the Observatoire de la Côte d'Azur to work towards the revival of intensity interferometry (Hanbury Brown and Twiss technique) with modern photonic technologies. This research topic is currently funded by the ANR project QuaCor and the ANR project I2C.
Nonlinear optics: superfluid light and self-organization
Atomic vapors have strong optical nonlinearities that we use in experiments with hot or cold vapors. In the latter case, the mechanical aspect plays also a role, with the spontaneous formation of atomic-density patterns. This research topic was initially funded by the EU project PhoQus and now continues with a CNRS prematuration grant.
Localization of light
When a wave propagates in a strongly disordered medium, it is predicted that above a certain level of disorder, interference effects completely block the wave diffusion. This so-called Anerderson localization has never been clealy observed for light. We have been studing, at a theoretical level, if and how a cold-atom cloud could be an appropriate medium for observing this effect. We are now building a new cold-atom experiment in order to experimentaly observe this effect.This research topic is currently funded by the ERC project ANDLICA.
Light-induced long-range forces
We also study the mechanical action of light on cold atoms during the multiple-scattering process. For example, it can give rise to mechanical instabilities, which we studied experimentally and theoretically. Moreover, it gives a force that is long-range, like Coulombian and gravitational interactions. As a consequence, there are interesting analogies with plasma physics and gravitational systems.
Main past projects:
- Random laser of light in cold atoms
- Lévy flights of light in hot vapors
- Matterwave in dynamical or complex potentials
- Coherent back scattering of light in cold atoms
- Laser cooling of strontium