© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Physical Review A

Predictions for laser-cooled Rb clocks

S. J. J. M. F. Kokkelmans, BOUDEWIJN J. VERHAAR, Kurt Gibble, Daniel J. Heinzen

Published Dec 1, 1997• 82 citations

Abstract

Using information from a recent ${}^{85}$Rb two-color photoassociation experiment, we evaluate the merits of fountain clocks based on ${}^{87}$Rb and ${}^{85}$Rb isotopes as alternatives to ${}^{133}$Cs and find that they offer significant advantages. In the case of ${}^{87}$Rb the collisionally induced fractional frequency shift is 15 times smaller than for ${}^{133}$Cs. This small shift is associated with a small difference in the triplet and singlet scattering lengths for ${}^{87}$Rb. For ${}^{85}$Rb, the shift produced by the two ${m}_{f}=0$ clock states may have opposite signs allowing the shift to be eliminated by controlling the relative populations of these states. We also present collision quantities relevant to atomic fountain clocks containing multiply launched groups of atoms, and for evaporative cooling of ${}^{85}$Rb atoms.

DOI: 10.1103/physreva.56.r4389

Related papers

Laser-cooled Rb fountain clocks

Chad Fertig, Ronald Legere, Wenko Süptitz +1 more

We demonstrate a prototype of a laser-cooled /sup 87/Rb fountain clock and report a preliminary measurement of the frequency shift due to cold collisions. We find the shift to be much smaller than that in a laser-cooled Cs clock. We have recently demonstrated a juggling atomic fountain to study cold collisions. We discuss the importance of juggling for future fountain clocks and the problems and potential solutions.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Jan 22, 2003•12 citations

Laser-cooled Rb clock

Chad Fertig, Jérémie Bouttier, Kurt Gibble

We demonstrate a prototype of a laser-cooled /sup 87/Rb fountain clock and measure the frequency shift due to cold collisions. The shift is fractionally 30 times smaller than that in a laser-cooled Cs clock. We observe a density dependent pulling by the microwave cavity and use it to cancel the collision shift. We have also demonstrated a juggling atomic fountain to study cold collisions and we discuss the importance of juggling for future fountain clocks.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Nov 8, 2002•8 citations

Laser-cooled Rb clocks

Chad Fertig, Ronald Legere, W. Suptitz +1 more

The authors present a preliminary measurement of the cold collision shift for /sup 87/Rb where they found the shift to be more than a factor of 10 smaller than that of a laser-cooled Cs clock. They also discuss calculations for /sup 85/Rb and demonstrate a juggling fountain. Juggling fountain clocks can achieve higher stability without requiring large improvements in the local oscillator. In this first Cs juggling experiment, the effects of collisions between juggled balls of atoms are studied.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Nov 27, 2002•0 citations

Laser-cooled microgravity clocks

Kurt Gibble

The principle advantage of microgravity for atomic clocks is interrogation times longer than 1 s. With a 10 s interrogation time, a clock has a 50 mHz linewidth suggesting that accuracies may potentially exceed 10/sup -16/. However, to achieve greater accuracy within the same averaging time, greater stability is needed. Achieving greater stability in a microgravity clock constrains the design differently than for earth based fountains. In this paper, we discuss the design considerations for laser-cooled microgravity clocks highlighting the considerations that differ from those for earth-based fountains. As in earthbased fountains, the frequency shift due to cold collisions plays an important role in the design of the clock. Given our predictions (and measurements) for the shift in laser-cooled Rb clocks, we currently anticipate building a high performance Rb clock and discuss the relative merits of Rb and Cs microgravity clocks. Finally, we present our tentative designs for two microgravity clocks.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Nov 27, 2002•7 citations

Laser-Cooled Rb Clock

Chad Fertig, Kurt Gibble

Abstract—We demonstrate a prototype of a laser-cooled 87Rb fountain clock. We report a preliminary measurement of the frequency shift due to cold collisions and find the shift to be at least a factor of ten less than that in a laser-cooled Cs clock. We also demonstrate the use of the ac Zeeman shift to measure the response of a microwave cavity. Finally, we have demonstrated a juggling atomic fountain and discuss the application of this technique to fountain and microgravity atomic clocks. Index Terms—Atomic clock, microwave resonators, microwave spectroscopy, rubidium materials/devices. I.

•Sep 8, 2016•1 citation

Laser-cooled /sup 87/Rb clock

Chad Fertig, Kurt Gibble

We demonstrate a prototype of a laser-cooled /sup 87/Rb fountain clock. We report a preliminary measurement of the frequency shift due to cold collisions and find the shift to be at least a factor of ten less than that in a laser-cooled Cs clock. We also demonstrate the use of the ac Zeeman shift to measure the response of a microwave cavity. Finally, we have demonstrated a juggling atomic fountain and discuss the application of this technique to fountain and microgravity atomic clocks.

IEEE Transactions on Instrumentation and Measurement•Apr 1, 1999•27 citations

Using information from a recent

{}^{85}

Rb two-color photoassociation experiment, we evaluate the merits of fountain clocks based on

{}^{87}

Rb and

{}^{85}

Rb isotopes as alternatives to

{}^{133}

Cs and find that they offer significant advantages. In the case of

{}^{87}

Rb the collisionally induced fractional frequency shift is 15 times smaller than for

{}^{133}

Cs. This small shift is associated with a small difference in the triplet and singlet scattering lengths for

{}^{87}

Rb. For

{}^{85}

Rb, the shift produced by the two

{m}_{f}=0

clock states may have opposite signs allowing the shift to be eliminated by controlling the relative populations of these states. We also present collision quantities relevant to atomic fountain clocks containing multiply launched groups of atoms, and for evaporative cooling of

{}^{85}

Rb atoms.

The principle advantage of microgravity for atomic clocks is interrogation times longer than 1 s. With a 10 s interrogation time, a clock has a 50 mHz linewidth suggesting that accuracies may potentially exceed 10/sup -16/. However, to achieve greater accuracy within the same averaging time, greater stability is needed. Achieving greater stability in a microgravity clock constrains the design differently than for earth based fountains. In this paper, we discuss the design considerations for laser-cooled microgravity clocks highlighting the considerations that differ from those for earth-based fountains. As in earthbased fountains, the frequency shift due to cold collisions plays an important role in the design of the clock. Given our predictions (and measurements) for the shift in laser-cooled Rb clocks, we currently anticipate building a high performance Rb clock and discuss the relative merits of Rb and Cs microgravity clocks. Finally, we present our tentative designs for two microgravity clocks.

Abstract—We demonstrate a prototype of a laser-cooled 87Rb fountain clock. We report a preliminary measurement of the frequency shift due to cold collisions and find the shift to be at least a factor of ten less than that in a laser-cooled Cs clock. We also demonstrate the use of the ac Zeeman shift to measure the response of a microwave cavity. Finally, we have demonstrated a juggling atomic fountain and discuss the application of this technique to fountain and microgravity atomic clocks. Index Terms—Atomic clock, microwave resonators, microwave spectroscopy, rubidium materials/devices. I.