Towards an Atom Laser: Cold Atoms in a Long High-gradient Magnetic Guide.

Atom Laser;Bose-Einstein Condensate;Magnetic Atom Guide;Rydberg Atoms;Laser Cooling and Trapping;Atom Optics;Physics;Science;Applied Physics

Mhaskar, Rahul RamdasWinick, Kim A. ;

University of Michigan

关键词: Atom Laser;    Bose-Einstein Condensate;    Magnetic Atom Guide;    Rydberg Atoms;    Laser Cooling and Trapping;    Atom Optics;    Physics;    Science;    Applied Physics;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/60753/rmhaskar_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 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.