Düsseldorf 2007 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 13: Präzisionsmessungen I
Q 13.1: Gruppenbericht
Montag, 19. März 2007, 16:30–17:00, 5L
Atomic microwave clocks at accuracy of 10−16 — •P. Rosenbusch1, S. Bize1, F. Chapelet1, C. Lacroute1, Ph. Laurent1, J. Reichel2, F. Reinhard1,2, D. Rovera1, G. Santarelli1, and A. Clairon1 — 1SYRTE, Observatoire de Paris, 61 Av. de l’Observatoire, 75014 Paris, France — 2LKB, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France
Today’s best microwave clocks are atomic fountains. About 109 atoms are laser cooled to 1µK and launched up vertically, where they pass through a microwave cavity. This Ramsey interrogation leads to a 1 Hz FWHM of the central fringe [S. Bize et al., J. Phys. B vol. 38, S449 (2005)]. Since 2006 the SYRTE disposes of three fountain clocks operating quasi-continuously, among other thanks to a new interference-filter stabilised laser system [X. Baillard et al., Opt. Comm., vol. 266, 609 (2006)]. Two fountains exhibit a relative stability of 2· 10−14 at 1 s and an accuracy in the low 10−16. A comparison between the fountains gave a statistical frequency resolution of a few 10−17 and an offset within the systematic uncertainties. Smaller microwave clocks may not reach the same performances but may well be the solution where transportability is required. The new project TACC (Trapped Atom Clock on a Chip) building on the demonstration experiment [P. Treutlein et al., Phys. Rev. Lett., vol. 92, 203005 (2004)] aims at a stability of a few 10−13 at 1 s while being of breadboard size. TACC will be able to operate with magnetically trapped thermal atoms or a Bose-Einstein condensate, thereby being one of the first experiments to use condensates in a metrological apparatus.