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Spectroscopie à deux lasers sur un systeme interdit à trois niveaux: 6S1/2-7S1/2-6P3/2 dans le césium

Abstract : Parity violation measurements in the 6S-7S transition of cesium agree, within the 10% accuracy, with the Standard Model of electromagnetic, weak, and strong interaction. However, fundamental features, such as electroweak corrections or the Z*-nucleon axial coupling, which are of the order of a few percent, have never been observed. A novel project, currently developed, aims at lmproving the detection efficiency (previously 1/2000) ; a probe laser, tuned to the 7S- 6P3/2 transition, will force the 7S atoms to emit in only one direction and only one transition. This dissertation describes the prelirninary experiments (and their theoretical interpretation) which allow a good understanding of the behaviour of cesium atoms in the presence of two c. w. lasers : one driving the highly forbidden 6S-7S transition, the other probing the allowed 7S-6P3/2 transition. The Cs-Cs collisionnal processes are taken into account. These experiments have shown that the probe beam does stimulate emission of the 7S atoms and is then amplified. We have also shown that an electronic polarization of the 7S atoms can be detected by two different methods using the probe beam : observation of the 7S-6P1/2 fluorescence (without polarisation analysis), or detection of the optical rotation of the probe beam. At the Cs density required for the planned parity-violation measurement, the Doppler-free spectra show complete resolution of the hyperflne structure of the 7S-6P3/2 transition. The detection of an electroweak alignment in the 7S level, on which the project is based, thus appears to be possible.
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Submitted on : Thursday, March 9, 2006 - 9:09:51 AM
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  • HAL Id : tel-00011861, version 1


Michel Lintz. Spectroscopie à deux lasers sur un systeme interdit à trois niveaux: 6S1/2-7S1/2-6P3/2 dans le césium. Physique Atomique [physics.atom-ph]. Université Paris Sud - Paris XI, 1987. Français. ⟨tel-00011861⟩



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