Absolute frequency measurements of the D<sub>1</sub> lines in <sup>39</sup>K, <sup>85</sup>Rb, and <sup>87</sup>Rb with ∼ 0.1 ppb uncertainty
A. Banerjee; D. Das; V. Natarajan; A. Banerjee; Department of Physics, Indian Institute of Science - Bangalore 560 012, India; D. Das; Department of Physics, Indian Institute of Science - Bangalore 560 012, India; V. Natarajan; Department of Physics, Indian Institute of Science - Bangalore 560 012, India
Журнал:
EPL (Europhysics Letters)
Дата:
2004-01-01
Аннотация:
We report values for the D<sub>1</sub>-line frequencies with 0.13 ppb uncertainty in the alkali atoms <sup>39</sup>K, <sup>85</sup>Rb, and <sup>87</sup>Rb. The frequencies are measured using an evacuated ring-cavity resonator whose length is calibrated against a reference laser locked to the D<sub>2</sub> line in <sup>87</sup>Rb. The measured frequencies, along with sub-ppb measurement of the atomic masses reported previously, form important links in a possible high-precision determination of the fine-structure constant using the photon-recoil shift measured in an atom interferometer. We also obtain, with improved precision, the hyperfine-coupling constants in the P<sub>1/2</sub> state of these atoms, and the fine-structure interval in the 5P state of Rb.
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