Dependence of the CPT resonance frequency of a cell with cesium vapors on the laser wave length

A.F. Kurchanov, A.S. Salnikov

FSUE «VNIIFTRI», Mendeleevo, Moscow region, Russia
kurchanov@vniiftri.ru,
salnikov@vniiftri.ru

Al’manac of Modern Metrology № 3 (27) 2021, pages 26–40

Annotation. The possibilities of selection of the total pressure of buffer gases in a cell with Cs vapors in such a way that the resonant CPT frequency does not depend on the laser wavelength and of shift of the laser wavelength from the absorption peak to reach the extremum of the standard frequency as a function of wavelength are considered.
It is shown experimentally that for cells with Cs and a mixture of Ne and Ar, the resonance CPT frequency decreases with increasing of laser wavelength at a mixture pressure of 100 Torr and increases at a mixture pressure of 120 Torr. Therefore, for a cell with a certain intermediate pressure, both the first and second derivatives of the dependence of the CPT resonance frequency from the laser wavelength at the peak of the transmission spectrum should vanish simultaneously. Such a cell, when used in quantum frequency standards, will improve their accuracy. The extrema of the standard frequency as a function of the laser wavelength are found. The shift of the operating wavelength of the laser from the peak of the transmission spectrum to such an extremum and its stabilization at this extremum improves the accuracy of the standard.

Key words: CPT resonance, cell with Cs vapors, buffer gas pressure, extrema.

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