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Etude expérimentale des phénomènes de transport dans les réseaux optiques d'atomes froids

Abstract : This thesis is devoted to the experimental study of transport phenomena in optical lattices of cold atoms, in particular bright lattices in which trapped atoms scatter light. The most important effects studied are spatial diffusion and Brillouin-like propagation modes. The experimental methods used in this work are pump-probe spectroscopy that we have used in two different configurations, recoil induced resonances for the study of kinetic temperature and imagery of the atomic cloud for the study of spatial diffusion and propagation modes.
The propagation modes, which have only been detected by pump-probe spectroscopy till then, have directly been detected by imagery for the first time: either by observing an increase of spatial diffusion or by observing a displacement of the center of mass of the atomic cloud in the direction of excitation.
The study of spatial diffusion for different geometries of the lattice has shown on one hand the anisotropy of spatial diffusion in a periodic lattice, and on the other hand the fact that spatial diffusion strongly depends on the lattice constant. By contrast, a study of kinetic temperature made simultaneously shows that the temperature does not depend on the lattice constant but only on the depth of the potential wells.
Finally, we have shown that the proposed relationship between the width of the central resonance observed in the pump-probe spectra (Rayleigh resonance) and the spatial diffusion coefficient, is not reliable. Other experimental studies are presented to check if the Rayleigh width can be related to the relaxation rate of the velocity distribution.
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https://tel.archives-ouvertes.fr/tel-00001556
Contributor : François-Régis Carminati <>
Submitted on : Monday, August 12, 2002 - 5:31:27 PM
Last modification on : Thursday, December 10, 2020 - 12:37:11 PM
Long-term archiving on: : Tuesday, September 11, 2012 - 5:40:36 PM

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  • HAL Id : tel-00001556, version 1

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François-Régis Carminati. Etude expérimentale des phénomènes de transport dans les réseaux optiques d'atomes froids. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2002. Français. ⟨tel-00001556⟩

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