Optical frequency measurements of 6s {sup 2}S{sub 1/2}-6p {sup 2}P{sub 1/2} (D{sub 1}) transitions in {sup 133}Cs and their impact on the fine-structure constant
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556-5670 (United States)
High resolution laser spectroscopy of the 6s {sup 2}S{sub 1/2}{yields}6p {sup 2}P{sub 1/2} transition (D{sub 1} line) in neutral {sup 133}Cs is performed in a highly collimated thermal atomic beam by use of a femtosecond laser frequency comb and narrow-linewidth diode laser. The diode laser is offset locked to a single frequency component of the femtosecond laser frequency comb and probes the optical transitions between selected pairs of ground-state and excited-state hyperfine components. A photodiode detects the excited-state decay fluorescence, and a computerized data acquisition system records the signal. The Doppler shift is eliminated by orienting the laser beam in a direction perpendicular to the atomic beam to within a precision of 5x10{sup -6} rad. Optical frequencies for all four pairs of hyperfine components are measured independently, from which the D{sub 1} line centroid and excited-state hyperfine splitting are obtained by least-squares minimization with the ground-state splitting as a fixed constraint. We find the D{sub 1} line centroid to be f{sub D{sub 1}}=335 116 048 748.1(2.4) kHz, and the 6p {sup 2}P{sub 1/2} state hyperfine splitting to be 1 167 723.6(4.8) kHz. These results, in combination with the results of an atom interferometry experiment by Wicht et al. [Phys. Scripta T 102, 82 (2002)], are used to calculate a new value for the fine-structure constant.
- OSTI ID:
- 20786899
- Journal Information:
- Physical Review. A, Vol. 73, Issue 3; Other Information: DOI: 10.1103/PhysRevA.73.032504; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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