In this seminar, I will present the latest developments of the new Rubidium experimental setup at College de France. This setup allows to produce two-dimensional (2D) degenerate gases in tailored in-plane potentials. This is enabled by the technical developments of (i) an “accordion” lattice that provides a variable 2D confinement and of (ii) arbitrary uniform potentials using a Digital Micromirror Device.
Using these techniques, we are able to produce slabs of atoms with a varying density and thickness. We study the interaction of these slabs with nearly resonant light. In the densest case, the mean interparticle distance is smaller than the wavelength, such that strong collective effects are expected.
We indeed observe a large broadening of the resonance curve, a non-lorentzian behavior in the far detuned regime as well as a blue shift of the resonance frequency which are qualitatively reproduced by our simulations. We also study the transport of the excitation in a locally illuminated cloud.