Berlin 2001 – scientific programme
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Q: Quantenoptik
Q 32: Poster: Laser Spectroscopy
Q 32.5: Poster
Friday, April 6, 2001, 12:30–15:00, AT2
A small cesium atomic clock — •S. Knappe1, J. Kitching2, H. G. Robinson2, L. Hollberg2, and R. Wynands1 — 1Institute for Applied Physics, Bonn University, Wegelerstraße 8, D-53115 Bonn, Germany — 2National Institute of Standards and Technology, Time and Frequency Division, M.S. 847.10, 325 S. Broadway, Boulder, CO 80303, USA
A low-cost, potentially compact and robust microwave frequency reference can be constructed using vertical-cavity surface-emitting lasers (VCSELs) and coherent population-trapping resonances (CPT) in cesium vapor cells. Fractional frequency instabilities of 2× 10−11/√τ/s have been achieved with a minimum of 7× 10−13 at τ=1000 s. The performance of this device was checked as a function of external parameters such as light intensity, optical detuning, and cell temperature, with particular attention to their influence on the output frequency of the clock. The short-term stability depends critically on the optical detuning through a newly-found effect of optical pumping, while the long-term stability is limited currently by line shifts due to drifts in cell temperature. The physics package of the clock can be engineered into a package 16× 18× 66 mm3 and could be run in an optimized version with less than 100 mW of electrical power. This small frequency reference could therefore find application for instance in GPS receivers or in base stations for mobile telecommunications.