Coherent population trapping resonances in Cs–Ne vapor microcells for miniature clocks applications

Abstract

Articles you may be interested inA low phase noise microwave frequency synthesis for a high-performance cesium vapor cell atomic clock Rev. Sci. Instrum. 85, 094709 (2014); 10.1063/1.4896043 Exploring Ramsey-coherent population trapping atomic clock realized with pulsed microwave modulated laser J. Appl. Phys. 115, 093109 (2014); 10.1063/1.4867915 Quasi-bichromatic laser for a lin⊥lin coherent population trapping clock produced by vertical-cavity surfaceemitting lasers Rev. Sci. Instrum. 83, 093111 (2012);We report the characterization of dark line resonances observed in Cs vapor microcells filled with a unique neon ͑Ne͒ buffer gas. The impact on the coherent population trapping ͑CPT͒ resonance of some critical external parameters such as laser intensity, cell temperature, and microwave power is studied. We show the suppression of the first-order light shift by proper choice of the microwave power. The temperature dependence of the Cs ground state hyperfine resonance frequency is shown to be canceled in the 77-80°C range for various Ne buffer gas pressures. The necessity to adjust the Ne buffer gas pressure or the cell dimensions to optimize the CPT signal height at the frequency inversion temperature is pointed out. Based on such Cs-Ne microcells, we preliminary demonstrate a 852 nm vertical cavity surface emitted laser ͑VCSEL͒-modulated based CPT atomic clock exhibiting a short term fractional frequency instability y ͑͒ = 1.5ϫ 10 −10 −1/2 until 30 s. These results, similar to those published in the literature by others groups, prove the potential of our original microcell technology in view of the development of high-performance chip scale atomic clocks.

Temperature and pressure shift of the Cs clock transition in the presence of buffer gases: Ne,N2, Ar

“…The inversion temperature computed from the coefficients of the fitted polynomials for each cell, in order to avoid pressure additional uncertainties, is T inv = (79 ± 3) • C, which confirms previous evaluations [18,36]. It makes Ne very attractive for use in the Cs chip scale clocks which need a high working temperature [37][38][39]. The calculated inversion temperature with N 2 is (164 ± 13) • C, while no inversion temperature can be given for Ar.…”

First-order cancellation of the Cs clock frequency temperature-dependence in Ne-Ar buffer gas mixture

“…At the same time and particularly, it has been measured in microcells [13] and cm-scale cells [9] that the Cs clock transition frequency shows a quadratic dependence on temperature around an inversion temperature of about 80 • C using only Ne as a unique buffer gas. In this case, it has been shown experimentally that the inversion temperature does not depend on the buffer gas pressure [14] as expected theoretically. This result could be of great interest for the development of simple configuration Cs CPT chip scale atomic clocks (CSAC) [15,16] operating typically in this temperature range.…”

Coherent-population-trapping resonances in buffer-gas-filled Cs-vapor cells with push-pull optical pumping

“…The temperature of each cell is set in order to maximize the CPT signal (see Table I). The cell 1 is microfabricated cell realized according to the process described in [46] and studied in [47] whereas cells 2 and 3 are glass-blown cm-scale pyrex vapor cells. The transmitted optical power through the cell is detected by a low noise photodiode.…”