Cold Atoms and Multiple Scattering

Robin Kaiser

David Wilkowski, Robin Kaiser, G. Labeyrie +5 more

We will present some experimental and theoretical studies on several dephasing processes that affect interference effects in multiple scattering of light in cold atomic samples: residual motion and internal structure of the scatterers, saturation of the atomic optical transition. All these processes reduce the CBS effect and should be circumvented in the quest for strong localization of light in cold atomic clouds.

Éric Akkermans, Ohad Assaf, Aharon Gero

Speckle patterns resulting from photon multiple scattering in cold vapors are studied using angular and time correlation functions. The effect of atomic collective states on the photon localization transition in cold atoms is studied.

Hasi Ray

A. Cipris, Mateus Antônio Fernandes Biscassi, J. C. C. Capella +9 more

Cold atomic clouds are promising platforms for generating correlated photons, but multiple scattering and associated Doppler broadening limit their temporal coherence. Here we demonstrate that cloud geometry provides a powerful means to extend the coherence time of scattered light. In the experiment, intensity-correlation measurements show that an elongated (quasi-1D) cloud exhibits systematically longer coherence times than a spherical (3D) cloud of the same on-axis optical thickness, as a direct consequence of the suppression of multiple scattering in the elongated geometry. Random-walk simulations reproduce this trend and further show that elongation drives the coherence time toward the single-scattering limit. The combined results establish cloud geometry as a robust control parameter for temporal coherence in cold-atom ensembles, with potential applications in quantum optics and communication.

Jean Dalibard, Christophe Salomon