title: Coherent Scattering of Near-Resonant Light by a Dense Microscopic Cold Atomic Cloud.
abstract: We measure the coherent scattering of light by a cloud of laser-cooled atoms with a size comparable to the wavelength of light. By interfering a laser beam tuned near an atomic resonance with the field scattered by the atoms, we observe a resonance with a redshift, a broadening, and a saturation of the extinction for increasing atom numbers. We attribute these features to enhanced light-induced dipole-dipole interactions in a cold, dense atomic ensemble that result in a failure of standard predictions such as the "cooperative Lamb shift". The description of the atomic cloud by a mean-field model based on the Lorentz-Lorenz formula that ignores scattering events where light is scattered recurrently by the same atom and by a microscopic discrete dipole model that incorporates these effects lead to progressively closer agreement with the observations, despite remaining differences.
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Jennewein
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France.
authors.forename: M
authors.initials: M
authors.lastname: Besbes
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France.
authors.forename: N J
authors.initials: NJ
authors.lastname: Schilder
authors.affiliation: Mathematical Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom.
authors.forename: S D
authors.initials: SD
authors.lastname: Jenkins
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Sauvan
authors.affiliation: Mathematical Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Ruostekoski
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France.
authors.forename: J-J
authors.initials: JJ
authors.lastname: Greffet
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France.
authors.forename: Y R P
authors.initials: YR
authors.lastname: Sortais
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Browaeys