Caesium atomic clocks: function, performance and applications

Bauch, A.

doi:10.1088/0957-0233/14/8/301

Cited by 80 publications

(42 citation statements)

References 58 publications

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“…As the competition for radio frequency bandwidth increases, other communication systems, commercial as well as military, may have to rely on atomic clocks to provide accurate frequency and time on board spacecraft. Satellite ranging for deep space will require an accuracy of 10 15 to 10 17 , (Allan et al 1994, Audoin and Guinot 2001, Bauch 2003, McCaskill et al 1999, Riehle 2004, Wu and Feess 2000.…”

Section: Positioning and Navigation On The Earth Surfacementioning

confidence: 99%

The Brazilian time and frequency atomic standards program

Ahmed

Magalhães

Bebeachibuli

et al. 2008

An. Acad. Bras. Ciênc.

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Cesium atomic beam clocks have been the workhorse for many demanding applications in science and technology for the past four decades. Tests of the fundamental laws of physics and the search for minute changes in fundamental constants, the synchronization of telecommunication networks, and realization of the satellite-based global positioning system would not be possible without atomic clocks. The adoption of optical cooling and trapping techniques, has produced a major advance in atomic clock precision. Coldatom fountain and compact cold-atom clocks have also been developed. Measurement precision of a few parts in 10 15 has been demonstrated for a cold-atom fountain clock. We present here an overview of the time and frequency metrology program based on cesium atoms under development at USP São Carlos. This activity consists of construction and characterization of atomic-beam, and several variations of cold-atom clocks. We discuss the basic working principles, construction, evaluation, and important applications of atomic clocks in the Brazilian program.

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Section: Positioning and Navigation On The Earth Surfacementioning

confidence: 99%

The Brazilian time and frequency atomic standards program

Ahmed

Magalhães

Bebeachibuli

et al. 2008

An. Acad. Bras. Ciênc.

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“…The time scales of NIST and PTB are compared continuously and the results are documented via the contributions that both laboratories make to the realization of international atomic time TAI [32]. In particular, the cesium fountains of both laboratories have been found to be in agreement to within their evaluated uncertainty of 1.0 · 10 −15 [2]. Combining the 1σ limits on the drift rates of the frequencies of Hg + and Yb + (cf.…”

Section: −15mentioning

confidence: 99%

“…Cesium fountain clocks with laser cooled atoms realize the SI second to an uncertainty of 1 · 10 −15 only [1,2]. Apart from counting, frequency metrology can also provide the most precise technique to determine a dimensionless quantity, if it is available in the form of a frequency ratio: a predetermined ratio of two optical frequencies was recently measured with an error of only 7 · 10 −19 [3].…”

Section: Introductionmentioning

confidence: 99%

Trapped Ion Optical Frequency Standards for Laboratory Tests of Alpha-Variability

Tamm

Schneider

Peik

2004

Astrophysics, Clocks and Fundamental Constants

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Abstract. Optical transition frequencies of trapped laser-cooled ions have been measured so far with an uncertainty of 10 −14 with reference to primary cesium clocks. Systematic frequency shifts in these systems should be controllable to significantly higher accuracy. We have performed comparisons between frequency standards based on two independently stored 171 Yb + ions. The present experimental results indicate a relative instability (Allan standard deviation) of the optical frequency difference between the two systems of 1.0·10−15 at an averaging time of 1000 s and a mean frequency difference of 0.2 Hz for the reference frequency of 688 THz. Monitoring the absolute transition frequency over a period of a few years at this level of accuracy will lead to a stringent limit on the present value of the temporal derivative of the fine-structure constant. First results have been obtained with a frequency standard based on 199 Hg + at NIST and, more recently, also with Yb + . The combination of results obtained with different transitions can be used to separate the electronic and nuclear contributions to a drift of a transition frequency. We propose optical spectroscopy of a nuclear transition in 229 Th 3+ as a means for a precision monitoring of possible temporal variations in the strength of the nuclear forces.

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“…These requirements are routinely met by commercial cesium or rubidium frequency standards that can be operated on site [10]. More stringent requirements to the frequency reference are set by high-precision experiments that demand a frequency uncertainty on the order of ≈1 × 10 −14 or below [11].…”

Section: Introductionmentioning

confidence: 99%

Optical frequency dissemination for metrology applications

Droste

Udem

Holzwarth

et al. 2015

Comptes Rendus. Physique

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Mots-clés :Fibre optique Transfert de fréquence Horloge atomique Lasers With the progress in the development of optical frequency standards grows the demand for the dissemination of stable optical frequencies. To date, optical fiber links constitute the most promising medium to bridge large geographical distances while still maintaining a high degree of frequency stability and accuracy. We investigated the transfer of an optical frequency along different fiber links during the past years and achieved a fractional instability and uncertainty at a level lower than 10 −19 using fiber links with lengths of up to almost 2000 km. We give an overview of different techniques and methods that can be used in combination with optical fiber links to achieve a stable frequency transfer. The results of different fiber links are summarized and an outlook of future links is given. © 2015 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.r é s u m é Avec les progrès réalisés dans le développement de standards de fréquences optiques, les besoins en matière de dissémination de fréquences optiques stables augmentent. À ce jour, la fibre optique constitue le moyen le plus prometteur pour relier de grandes distances géographiques tout en maintenant une haute exigence en matière de stabilité et de précision en fréquence. Nous avons étudié le transfert d'une fréquence optique par différentes fibres au cours des dernières années et avons atteint une instabilité fractionnelle et une imprécision à un niveau inférieur à 10 −19 pour des fibres optiques couvrant une longueur de presque 2000 km. Nous donnons un aperçu de différentes techniques et méthodes qui peuvent être utilisées en combinaison avec des fibres optiques pour obtenir un transfert de fréquence stable. Les résultats obtenus pour différentes fibres optiques sont résumés et un aperçu des futurs développements du transfert par fibre est donné.

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Caesium atomic clocks: function, performance and applications

Cited by 80 publications

References 58 publications

The Brazilian time and frequency atomic standards program

The Brazilian time and frequency atomic standards program

Trapped Ion Optical Frequency Standards for Laboratory Tests of Alpha-Variability

Optical frequency dissemination for metrology applications

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