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Towards an Atom Laser: Cold Atoms in a Long High-gradient Magnetic Guide.
[摘要] The propagation of an atomic beam through a 1.7 m long magnetic guide with magnetic field gradient of up to 2.7 kGauss/cm has been demonstrated. The guide is side-loaded with an atomic beam from a Pyramidal MOT Low-velocity Intense Source. The atomic beam observed at the end of the guide has a flux of 3×10e7 atoms/s with a velocity of 1.2 m/s, a transverse temperature of 420±40 μK and a longitudinal temperature of 1 mK. The guided atomic beam was mode-filtered by selective removal of high-energy atoms using radio-frequency coupling to magnetically untrapped states. We found that the phase-space density of the atomic beam was very low for evaporative cooling to be functional.An imaging technique was developed to characterize the guided atomic flow in the presence of a high magnetic field gradient. This technique utilizes the open-channeltransition to obtain nearly constant photon yield per atom independent of the location of the atom in the guide, providing a mapping of the fluorescence images to the atomic-density profiles. This technique was theoretically studied using Quantum Monte-Carlo Simulations and validated.A Zeeman slower was constructed and characterized to be used as the primary source of atoms to the magnetic guide. The Zeeman slower output atomic beam has a flux of 3×10e11 atoms/s at a velocity of 40 m/s. We have designed a new injection scheme to transfer atoms from the Zeeman slower to the magnetic guide efficiently. The details of a new method to evaporatively cool atoms in the magnetic guide using surface adsorption are described. Finally, a new guide geometry based on a spiral structure is discussed.
[发布日期]  [发布机构] University of Michigan
[效力级别] Bose-Einstein Condensate [学科分类] 
[关键词] Atom Laser;Bose-Einstein Condensate;Magnetic Atom Guide;Rydberg Atoms;Laser Cooling and Trapping;Atom Optics;Physics;Science;Applied Physics [时效性] 
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