Optics Express

A chip-scale atomic clock based on ^87Rb with improved frequency stability

Svenja A. Knappe, Peter D. D. Schwindt, Vishal Shah, Leo W. Hollberg, John E. Kitching, Li‐Anne Liew, John Moreland

Published Jan 1, 2005• 238 citations

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 degrees 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 x?10-11 / tau?/2 and the improvement over the Cs device is due mainly to an increase in resonance amplitude. At longer times (tau?> 50 s), the improvement results from the reduction of a slow drift to ?5 x 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.

DOI: 10.1364/opex.13.001249

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