Abstract

We demonstrate a microfabricated atomic clock physics package based on coherent population trapping (CPT) on the D1 line of 87Rb atoms. The package occupies a volume of 12 mm3 and requires 195 mW of power to operate at an ambient temperature of 200 °C. Compared to a previous microfabricated clock exciting the D2 transition in Cs [1], this 87Rb clock shows significantly improved short- and long-term stability. The instability at short times is 4×10-111/2 and the improvement over the Cs device is due mainly to an increase in resonance amplitude. At longer times (τ>50 s), the improvement results from the reduction of a slow drift to -5×10-9/day. The drift is most likely caused by a chemical reaction of nitrogen and barium inside the cell. When probing the atoms on the D1 line, spin-exchange collisions between Rb atoms and optical pumping appear to have increased importance compared to the D2 line.

© 2005 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
  12. W. Franzen and A.G. Emslie, “Atomic Orientation by Optical Pumping,” Phys. Rev. 108, 1453-1458 (1957).
    [CrossRef]

2003 IEEE International Frequency Contro

S. Knappe, V. Velichansky, H.G. Robinson, L. Liew, J. Moreland, J. Kitching, and L. Hollberg, ”Atomic Vapor Cells for Miniature Frequency References,” in Proc. of the 2003 IEEE International Frequency Control Symposium and PDA Exhibition Jointly with the 17th European Frequency and Time Forum, (Institute of Electrical and Electronics Engineers, New York, 2003), 31-32.

34th Annual Precise Time and Time Interv

R. Lutwak, D. Emmons, T. English, W. Riley, A. Duwel, M. Varghese, D.K. Serkland, G.M. Peake, “The Chip-Scale Atomic Clock - Recent Development Progress,” in Proc. 34th Annual Precise Time and Time Interval Systems and Applications Meeting, San Diego, CA, December 2-4, 2003.

Appl. Phys.

L. Liew, S. Knappe, J. Moreland, H.G. Robinson, L. Hollberg, and J. Kitching, “Microfabricated alkali atom vapor cells,” Appl. Phys. Lett. 48, 2694-2696 (2004).
[CrossRef]

Appl. Phys. Lett.

S. Knappe, V. Shah, P. Schwindt, L. Hollberg, J. Kitching, L. Liew, J. Moreland, ”A microfabricated atomic clock,” Appl. Phys. Lett. 85, 1460-1462 (2004) .
[CrossRef]

J. Appl. Phys.

P. R. Wallis and D. I. Pomeranz, “Field Assisted Glass-Metal Sealing,” J. Appl. Phys. 40, 3946-3949 (1969).
[CrossRef]

Opt. Lett.

Phys. Rev.

W. Franzen and A.G. Emslie, “Atomic Orientation by Optical Pumping,” Phys. Rev. 108, 1453-1458 (1957).
[CrossRef]

Pro.c 33rd Ann. PTTI Systems and Applica

H. Fruehoff, “Fast "direct-P(Y)" GPS signal acquisition using a special portable clock,” in Pro.c 33rd Ann. Precise Time and Time Interval (PTTI) Systems and Applications Meeting, Long Beach, CA, November 27- 29, 359-369 (2001).

Progress in Optics XXXV

E. Arimondo, “Coherent population trapping in laser spectroscopy,” in, Progress in Optics XXXV, E. Wolf, eds. (Elsevier, Amsterdam,1996), pp. 257-354.

Rev. Mod. Phys.

W. Happer, “Optical pumping,” Rev. Mod. Phys. 44, 169-242 (1972).
[CrossRef]

RF design

J. A. Kusters and C.A. Adams, “Performance requirements of communication base station time standards,” RF design, 28-38 (1999).

Other

J. Vig, “Military applications of high-accuracy frequency standards and clocks,” 40, 522-527 (1993).

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Figures (3)

Fig. 1.
Fig. 1.

(a) Picture of the 87Rb D1 CSAC physics package. (b) Level diagram of 87Rb.

Fig. 2.
Fig. 2.

Measured Allan deviation for the 87Rb D1 CSAC (red dots). It shows a clear improvement in stability over the first CSAC [1], which was based on the Cs D2 line (blue squares).

Fig. 3.
Fig. 3.

Measured clock frequency normalized to the hyperfine frequency as a function of time for the 87Rb D1 CSAC (red). It can be seen that the slow frequency drift is reduced compared to the first Cs D2 CSAC (blue).

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