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Etude du refroidissement laser en cellule : contribution au développement d´une horloge atomique miniature à Cs133

Abstract : The aim of the Horace project is the realisation of on-board high frequency performance and compact atomic clocks thanks to cold Cs atoms. In this thesis, we first discuss the original operation of Horace, where all interactions are applied in the micro-wave cavity (cooling, interrogation and detection), according to a pure temporal scheme. We show that the relative frequency stability can be <1.10^(-12)\tau^(-1/2), depending on one hand on the cooling features, as the atomic cloud size and the capture rate, and on the other hand on the frequency performances of the local oscillator at Fourier frequency of a few 10 Hz (aliasing effect). Detection schemes by fluorescence (population) and radiation damping (coherences) are described and discussed. The second part of the thesis depicts a Doppler model in a reflective or diffusive cell, on the basis of the study of the mean laser field in the cell. Then we show that the 3D speckle pattern allows Sisyphus cooling to occur. The third part of the thesis is devoted to the experimental study of sub-Doppler cooling in a optically polished reflective spherical micro-wave cavity, used as a cell. The study demonstrates that more than 3.10^(7) cold atoms are cooled in the 3D speckle light wells. Thermalization times ~30-fold longer than in a Lin per Lin configuration were observed, as predicted by theory. Time-of-flight measurements revealed temperatures as low as ~ 2 microK. The last part of the thesis describes the realisation and the tuning of a spherical microwave cavity, and the main relative frequency shifts expected in the accuracy budget of Horace. Namely this is the phase shift due to the micro-wave switch and the collisional relative frequency shift, both expected at a few 10^(-13) level.
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Contributor : Paul-Eric Pottie <>
Submitted on : Wednesday, May 5, 2004 - 6:55:04 PM
Last modification on : Monday, December 14, 2020 - 9:48:23 AM
Long-term archiving on: : Friday, April 2, 2010 - 8:29:56 PM

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  • HAL Id : tel-00006012, version 1

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Paul-Eric Pottie. Etude du refroidissement laser en cellule : contribution au développement d´une horloge atomique miniature à Cs133. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2003. Français. ⟨tel-00006012⟩

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