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Limitations of Long-Term Stability in a Coherent Population Trapping Cs Clock

2014; Institute of Electrical and Electronics Engineers; Volume: 63; Issue: 7 Linguagem: Inglês

10.1109/tim.2014.2298672

1557-9662

Olga Kozlova, Jean-Marie Danet, Stéphane Guérandel, Emeric de Clercq,

Advanced Frequency and Time Standards

Vapor cell atomic clocks exhibit reduced frequency stability for averaging time between about one hundred and a few thousand seconds. Here we report a study on the impact of the main parameters on the mid-to-long term instability of a buffer-gas vapor cell Cs clock, based on coherent population trapping (CPT). The CPT signal is observed on the Cs D1 line transmission, using a double $\Lambda$ scheme and a Ramsey interrogation technique. The effects on the clock frequency of the magnetic field, the cell temperature, and the laser intensities are reported. We show in particular that the laser intensity shift is temperature dependent. Along with the laser intensity ratio and laser polarization properties, this is one of the most important parameters.