Antoine Browaeys

This talk will present recent experiments that we performed on the study of near-resonance light scattering in dense laser-cooled and hot atomic vapors. In both cases, the large density results in a strong influence of the interactions between light-induced dipoles. We will compare our measurements of the coherent scattering on both systems to theoretical models and show that while the qualitative behaviors are correctly reproduced for hot and cold vapors, the quantitative agreement is only achieved in the hot vapor case. The talk will also come back to the origin of the collective Lamb shift in hot atomic vapors and present it as an indirect consequence of the dipole-dipole interactions between atoms.