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Mesure de deux caractéristiques de l'hélium métastable importantes pour le refroidissement radiatif

Julie Poupard 1
1 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique
LCFIO - Laboratoire Charles Fabry de l'Institut d'Optique
Abstract : This thesis presents the study of two characteristics of metastable helium that are important for laser cooling. First, we measure two-body losses in a magneto-optical trap. The losses, enhanced by nearly resonant laser radiation, are mainly due to ionizing collisions. We measure the loss rate by observing the decay of the number of trapped atoms using either atomic fluorencence or ion production. We study the loss rate as a function of the trapping laser parameters. The second part of the thesis concerns experiments to measure the transition rates of the intercombination lines: 2^3P_1 to 1^1S_0 and 2^3P_2 to 1^1S_0. The first of these rates is measured by exciting a small fraction of the atoms in a magneto-optical trap to the 2^3P_1 state and observing the decrease in the trap lifetime. We then measure the ratio of the transition rates for 2^3P_1 and 2^3P_2 towards the 1^1S_0 ground state by monitoring the flux of UV photons associated with the transition.
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https://pastel.archives-ouvertes.fr/tel-00193850
Contributor : Christoph I Westbrook <>
Submitted on : Tuesday, December 4, 2007 - 5:14:30 PM
Last modification on : Wednesday, October 14, 2020 - 3:41:43 AM
Long-term archiving on: : Monday, April 12, 2010 - 6:06:55 AM

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  • HAL Id : tel-00193850, version 1

Citation

Julie Poupard. Mesure de deux caractéristiques de l'hélium métastable importantes pour le refroidissement radiatif. Physique Atomique [physics.atom-ph]. Université Paris Sud - Paris XI, 2000. Français. ⟨tel-00193850⟩

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