The Optically Pumped Cs Frequency Standard at the NRLM
NATIONAL RESEARCH LAB OF METROLOGY TSUKUBA SCIENCE CITY (JAPAN)
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The optically pumped Cs frequency standard is being developed at the NRLM, and the construction is almost finished. Its microwave cavity length is 0.96m, and the dimensions are almost the same as the conventional type frequency standards at the NRLM. Light sources for optical pumping and detection, whose frequencies are stabilized by means of saturated absorption spectra of Cs, are also developed. Using this apparatus, we could observe Ramsey resonance signal and could confirm the two frequency pumping effect. In addition, pumping with a polarized laser light, we also confirmed that the magnetic field could be measured using Zeeman coils in the same way of conventional type. Since an optically pumped Cs frequency standard using laser diodes was proposed, basic experiments carried out and frequency standards based on this new method are being realized at several laboratories. At the National Research Laboratory of Metrology NRLM, the development of this type of standard aiming a primary frequency standard was started in 1984. Its dimensions are made to be almost the same as the NRLM-II and the NRLM-III this is also a newly developed conventional type standard for the purpose of comparing both types. The other conditions, for example the degree of vacuum, magnetic shields, etc., are also almost the same. As the construction was almost finished, some preliminary experiments were carried out to confirm the fundamental functions of this standard and to find out the problems of the apparatus. This paper describes the construction of the optically pumped Cs frequency standard developed at the NRLM using photographs and some results of the preliminary experiments.
- Test Facilities, Equipment and Methods
- Atomic and Molecular Physics and Spectroscopy