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Expériences d interférométrie atomique avec l'atome de lithium

Marion Jacquey 1
1 Interférométrie (LCAR)
LCAR - Laboratoire Collisions Agrégats Réactivité
Abstract : This study presents the tuning of a Mach Zehnder atom interferometer and its operation for interferometric measurements. A supersonic beam of lithium is coherently manipulated by elastic Bragg diffraction on laser standing waves almost resonant with the first resonance transition of lithium atom at 671 nm. A model of the interferometer, based on simulations of the diffraction process, is used to precisely describe the selectivity with respect to atom velocity and incidence angle. The apparatus exhibits interference fringes with an excellent visibility, up to 84.5 %, for the first diffraction order. The visibility for second or third order diffraction are significantly reduced. The most important contribution to this visibility loss is due to the phase noise induced by mechanical vibrations of the interferometer. The quality of signals with first diffraction order is used to perform two interferometric measurements. The application of an electric field on only one of the two atomic beams, separated by 90 microns, induces a phase shift which provides an accurate measurement of the electric polarizability of lithium atom, alpha= (24.34 ± 0.16) 10-30 m3, in excellent agreements with the most precise calculations. By inserting a gas cell on one arm of the interferometer, we measure the refractive index n of gases (Ar, Kr, Xe) for lithium waves. The linearity of (n-1) as a function of gas density is well verified. By changing the lithium atomic wavelength, we are able to observe glory oscillations on the real and imaginary parts of n and also on their ratio rho. These measurements are compared to measurements of the total cross section for the imaginary part of n and to calculations for the real part and the ratio rho: in all cases, a good agreement is found.
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Submitted on : Wednesday, February 7, 2007 - 4:40:56 PM
Last modification on : Friday, February 28, 2020 - 1:52:03 PM
Long-term archiving on: : Friday, September 21, 2012 - 11:13:04 AM

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  • HAL Id : tel-00129507, version 1

Citation

Marion Jacquey. Expériences d interférométrie atomique avec l'atome de lithium. Physique Atomique [physics.atom-ph]. Université Paul Sabatier - Toulouse III, 2006. Français. ⟨tel-00129507⟩

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