Cold-Atom Clocks on Earth and in Space

  • Pierre Lemonde
  • Philippe Laurent
  • Giorgio Santarelli
  • Michel Abgrall
  • Yvan Sortais
  • Sébastien Bize
  • Christophe Nicolas
  • Shougang Zhang
  • André Clairon
  • Noël Dimarcq
  • Pierre Petit
  • Antony G. Mann
  • Andre N. Luiten
  • Sheng Chang
  • Christophe Salomon
Part of the Topics in Applied Physics book series (TAP, volume 79)


We present recent progress on microwave clocks that make use of lasercooled atoms. With an ultra-stable cryogenic sapphire oscillator as interrogation oscillator, a cesium fountain operates at the quantum projection noise limit. With 6 × 105 detected atoms, the relative frequency stability is 4 × 10−14 τ −1/2, where τ is the integration time in seconds. This stability is comparable to that of hydrogen masers. At τ = 2 × 104 s, the measured stability reaches 6 × 10−16. A 87Rb fountain has also been constructed and the 87Rb ground-state hyperfine energy has been compared to the Cs primary standard with a relative accuracy of 2.5 × 10−15. The 87Rb collisional shift is found to be at least 30 times below that of cesium. We also describe a transportable cesium fountain, which will be used for frequency comparisons with an accuracy of 10−15 or below. Finally, we present the details of a space mission for a cesium standard which has been selected by the European Space Agency (ESA) to fly on the International Space Station in 2003.


European Space Agency Frequency Stability Frequency Standard Detection Zone Hydrogen Maser 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Pierre Lemonde
    • 1
  • Philippe Laurent
    • 1
  • Giorgio Santarelli
    • 1
  • Michel Abgrall
    • 1
  • Yvan Sortais
    • 1
  • Sébastien Bize
    • 1
  • Christophe Nicolas
    • 1
  • Shougang Zhang
    • 1
  • André Clairon
    • 1
  • Noël Dimarcq
    • 2
  • Pierre Petit
    • 2
  • Antony G. Mann
    • 3
  • Andre N. Luiten
    • 3
  • Sheng Chang
    • 3
  • Christophe Salomon
    • 4
  1. 1.Observatoire de ParisBNM-LPTFParisFrance
  2. 2.Laboratoire de l’horloge atomiqueOrsayFrance
  3. 3.Physics DepartmentUniversity of Western AustraliaNedlandsAustralia
  4. 4.Département de Physique de l’Ecole Normale SupérieureLaboratoire Kastler BrosselParisFrance

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