# PHARAO: ÉTUDE D'UNE HORLOGE SPATIALE UTILISANT DES ATOMES REFROIDIS PAR LASER; RÉALISATION D'UN PROTOTYPE

Abstract : The performances of atomic clocks have been drastically improved in
the last few years thanks to laser cooling techniques. Indeed,
extremely slow atoms can be observed much longer than the room
temperature atoms used in conventional clocks. Today, the best
cesium clock has an accuracy of $2\times 10^(-15)$ and a stability
of $1\times 10^(-15)$ after a three hours integration time. On
earth, the observation time of the atoms is limited to one second
due to the presence of gravity. This thesis is devoted to the study
of a micro-gravity clock using laser cooled atoms. In the first
part, we show how this environment can lead to better performances
with a several seconds observation time of the atoms. The ultimate
performances of a cold atom clock in space are investigated. It
seems realistic to reach in the short term an accuracy and a
stability per day of $1\times10^(-16)$. The interrogation scheme of
the atoms has to be reconsidered at this level of performances and
in the environment of absence of gravity. We introduce the
sensitivity function to solve this problem and compare different
possible interrogation scheme. The second part of the thesis
describes a prototype of the space clock. Compact and reliable, it
has been tested in the reduced gravity of aircraft parabolic
flights. This experiment shows the feasibility of the future space
clock.
Mots-clés :
Document type :
Theses
Atomic Physics [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 1997. French

https://tel.archives-ouvertes.fr/tel-00003883
Contributor : Pierre Lemonde <>
Submitted on : Tuesday, December 2, 2003 - 6:42:29 PM
Last modification on : Saturday, January 21, 2006 - 9:06:26 PM

### Identifiers

• HAL Id : tel-00003883, version 1

### Citation

Pierre Lemonde. PHARAO: ÉTUDE D'UNE HORLOGE SPATIALE UTILISANT DES ATOMES REFROIDIS PAR LASER; RÉALISATION D'UN PROTOTYPE. Atomic Physics [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 1997. French. <tel-00003883>

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