A cesium fountain frequency standard: preliminary results

Clairon, A.; Laurent, Philippe; Santarelli, G.; Ghezali, S.; Lea, S. N.; Bahoura, M.

doi:10.1109/19.377790

Cited by 149 publications

(71 citation statements)

References 13 publications

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“…The first one (FO1), in operation since 1994 [5], has been refurbished recently. The second one (FOM), a transportable fountain, is derived from the PHARAO space clock prototype [9].…”

Section: Recent Advances In Cesium and Rubidium Fountainsmentioning

confidence: 99%

“…Precision measurements with neutral atoms on the other hand are usually performed in an atomic fountain where laser cooled atoms ballistically propagate for durations up to one second. In the last decade, atomic clocks and inertial sensors using matter wave interferometry in fountains have become two of the most important applications of cold atoms [3,5]. About two dozens of fountain devices are now used for a variety of applications.…”

Section: Atomic Fountainsmentioning

confidence: 99%

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Cold atom clocks and applications

Bize

Laurent

Abgrall

et al. 2005

J. Phys. B: At. Mol. Opt. Phys.

223

161

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This paper describes advances in microwave frequency standards using laser-cooled atoms at BNM-SYRTE. First, recent improvements of the 133 Cs and 87 Rb atomic fountains are described. Thanks to the routine use of a cryogenic sapphire oscillator as an ultra-stable local frequency reference, a fountain frequency instability of 1.6 × 10 −14 τ −1/2 where τ is the measurement time in seconds is measured. The second advance is a powerful method to control the frequency shift due to cold collisions. These two advances lead to a frequency stability of 2 × 10 −16 at 50 000 s for the first time for primary standards. In addition, these clocks realize the SI second with an accuracy of 7 × 10 −16 , one order of magnitude below that of uncooled devices. In a second part, we describe tests of possible variations of fundamental constants using 87 Rb and 133 Cs fountains. Finally we give an update on the cold atom space clock PHARAO developed in collaboration with CNES. This clock is one of the main instruments of the ACES/ESA mission which is scheduled to fly on board the International Space Station in 2008, enabling a new generation of relativity tests.

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“…The first one (FO1), in operation since 1994 [5], has been refurbished recently. The second one (FOM), a transportable fountain, is derived from the PHARAO space clock prototype [9].…”

Section: Recent Advances In Cesium and Rubidium Fountainsmentioning

confidence: 99%

Section: Atomic Fountainsmentioning

confidence: 99%

Cold atom clocks and applications

Bize

Laurent

Abgrall

et al. 2005

J. Phys. B: At. Mol. Opt. Phys.

223

161

View full text Add to dashboard Cite

show abstract

“…After the acceleration process described later, the atomic velocity distribution is probed using a second Raman π-pulse from F=1 to F=2 ( Fig.1.Right). The population in both levels is detected using a time of flight technique [9] . The Raman beams are produced by two stabilized laser diodes.…”

mentioning

confidence: 99%

Determination of the Fine Structure Constant Based on Bloch Oscillations of Ultracold Atoms in a Vertical Optical Lattice

et al. 2006

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We report an accurate measurement of the recoil velocity of 87 Rb atoms based on Bloch oscillations in a vertical accelerated optical lattice. We transfer about 900 recoil momenta with an efficiency of 99.97% per recoil. A set of 72 measurements of the recoil velocity, each one with a relative uncertainty of about 33 ppb in 20 min integration time, leads to a determination of the fine structure constant α with a statistical relative uncertainty of 4.4 ppb. The detailed analysis of the different systematic errors yields to a relative uncertainty of 6.7 ppb. The deduced value of α −1 is 137.03599878(91).

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“…Especially, cold neutral atoms are also being used in the development of new microwave clocks [7,8]. In this Letter we report for the first time on atom interferometric high resolution measurements of an optical transition with a line Q factor above 10 12 corresponding to a resolved linewidth well below 1 kHz.…”

mentioning

confidence: 94%

Sub-Kilohertz Optical Spectroscopy with a Time Domain Atom Interferometer

et al. 1998

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We report on the sub-kilohertz optical spectroscopy on the 1 S 0 -3 P 1 intercombination transition in magnesium at 457 nm. The spectroscopic signal is probed by a time domain atom interferometer. The realization of this time domain atom interferometer with laser cooled and trapped atoms allows extremely long interaction times and leads to resolutions down to 491 Hz (FWHM). This corresponds to a high line Q factor of 1.3 3 10 12 . Because of the high accuracy in the determination of the line center, applications with respect to an optical frequency standard are possible. [S0031-9007(98) PACS numbers: 03.75. Dg, 39.20. + q, 39.30. + w, In recent years the field of atom interferometry [1] has opened up new areas in fundamental and applied atomic physics. This is based mainly on the small wavelength of atomic de Broglie waves leading to the high sensitivity of atomic interferometers. In parallel the operation of atom interferometers has shown that due to the small de Broglie wavelength the proposed high sensitivity demands a setup of highest mechanical stability. Very recently several atom interferometric measurements have reached or even surpassed the precision of conventional "state of the art methods." Prominent examples are the realization of a highly sensitive atom-based Sagnac gyroscope [2], the measurement of the Earth's gravitational acceleration [3], and the precise determination ofh͞m atom [4].The Ramsey-Bordé atom interferometer, in particular, has proven to have excellent perspectives for applications in high resolution spectroscopy [1]. In this type of atom interferometer, the atomic wave is split and the partial waves are reflected and recombined by nearly resonant laser light. The phase shift between the two interfering matter waves depends strongly on the frequency of the splitting laser beam producing the spectroscopic signal. The transfer of the Ramsey-Bordé scheme from the originally proposed beam experiment [5] to a time domain interferometer [6] increases the sensitivity and reduces systematic line shifts by several orders of magnitude.Different methods for high resolution optical spectroscopy on neutral atoms as well as ions are currently being discussed and evaluated in the context of the next generation of frequency standards and atomic clocks. Especially, cold neutral atoms are also being used in the development of new microwave clocks [7,8]. In this Letter we report for the first time on atom interferometric high resolution measurements of an optical transition with a line Q factor above 10 12 corresponding to a resolved linewidth well below 1 kHz. The results presented here should be compared to recent results from the methods of the two-photon spectroscopy [9] and spectroscopy on single trapped ions [10]. In two-photon spectroscopy the ac Stark shift affects the obtainable accuracy, whereas in single-ion spectroscopy the stability is limited by the small particle numbers. The atom interferometric measurement of optical transitions discussed here offers the combination of a high accuracy...

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A cesium fountain frequency standard: preliminary results

Cited by 149 publications

References 13 publications

Cold atom clocks and applications

Cold atom clocks and applications

Determination of the Fine Structure Constant Based on Bloch Oscillations of Ultracold Atoms in a Vertical Optical Lattice

Sub-Kilohertz Optical Spectroscopy with a Time Domain Atom Interferometer

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