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Source atomique cohérente dans des pièges optique et magnétique: réalisation d'un laser à atomes guidé

William Guerin 1
1 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique
LCFIO - Laboratoire Charles Fabry de l'Institut d'Optique
Abstract : An "atom laser" is an atomic beam extracted from a Bose-Einstein condensate, which is a cloud of trapped atoms, cooled down to quantum degeneracy. For the prospect to use this coherent atomic source in future applications, as for instance precision atom interferometry, a sufficient control over the beam properties is needed. In particular, some characteristics make atom lasers different from photonic lasers, as the strong interaction between atoms, and their sensitivity togravity.
In our thesis, we report a study of the transverse mode of an atom laser, and we show that it is highly degraded by interactions with the source-condensate. By extending the formalism of photonic laser optics, we characterize the beam by a quality factor M2.
In a second part, we demonstrate a method allowing to cancel the effect of gravity, which usually accelerates the atoms, thus causing a rapid decrease of the matterwave de Broglie wavelength. We use an optical waveguide, consisting of a very elongated dipole trap, to guide the atom laser horizontally. We thus obtain an atom laser with a constant wavelength over the propagation, at a value of 0.5 μm. In order to efficiently couple the beam into the guide, we produce the condensate in the hybrid trap obtained at the intersection of the optical guide and a magnetic trap. We show that this configuration ensures an intrinsically good transverse mode matching.
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https://pastel.archives-ouvertes.fr/tel-00146375
Contributor : William Guerin <>
Submitted on : Tuesday, June 3, 2008 - 11:20:51 PM
Last modification on : Friday, October 23, 2020 - 4:51:25 PM
Long-term archiving on: : Tuesday, September 21, 2010 - 4:30:06 PM

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  • HAL Id : tel-00146375, version 2

Citation

William Guerin. Source atomique cohérente dans des pièges optique et magnétique: réalisation d'un laser à atomes guidé. Physique Atomique [physics.atom-ph]. Université Paris Sud - Paris XI, 2007. Français. ⟨tel-00146375v2⟩

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