Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)

Comparison of achievable performances as regards rubidium gas cell frequency standards with continuous and pulse laser pumping and with coherent population trapping

V. S. Zholnerov, A. Besedina, Georgy A. Kazakov

Published Apr 1, 2009• 1 citation

Publisher

Abstract

We report the results of mathematical modeling the frequency stability for three types of rubidium gas cell frequency standards : with continuous and pulse laser pumping and with coherent population trapping (CPT). A critical point for using laser pumping in RFS which defines essentially the frequency stability is the influence of laser emission's frequency fluctuations. The effect of these fluctuations on frequency stability of RFS variants' considered is analyzed. Based on studies performed, the achievable stability for these RFS variants are compared.

DOI: 10.1109/freq.2009.5168250

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Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)

Comparison of achievable performances as regards rubidium gas cell frequency standards with continuous and pulse laser pumping and with coherent population trapping

V. S. Zholnerov, A. Besedina, Georgy A. Kazakov

Published Apr 1, 2009• 1 citation

Publisher

Abstract

DOI: 10.1109/freq.2009.5168250

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{}_{2}

) buffer-gas pressure in micro-fabricated vapor cells containing natural-abundance rubidium (Rb) generated from Rb azide (RbN

{}_{3}

) for chip-scale atomic clocks. A wafer-level fabrication method enabling individual control of N2 pressure was developed by inkjet patterning of RbN3 and subsequent krypton fluoride (KrF) excimer laser decomposition. An increasing N2 pressure was found to reduce the CPT linewidth and cause a significant decrease in the signal amplitude, which resulted in monotonic degradation in the CPT figure of merit with higher pressures. A CPT-based laser frequency stabilization method that locked the laser wavelength to the CPT resonance peak yielded significantly larger signal amplitudes than a conventional absorption-based method in the low-pressure regime below 8 kPa. These results show that CPT performance in micro-fabricated Rb vapor cells is more restricted by the signal amplitude rather than the linewidth. They also offer practical buffer-gas design guidelines for enhancing short-term frequency stability in chip-scale atomic clocks.