High performance vapour-cell frequency standards

We demonstrate a high-performance coherent-population-trapping (CPT) Cs vapor cell atomic clock using the push-pull optical pumping technique (PPOP) in the pulsed regime, allowing the detection of high-contrast and narrow Ramsey-CPT fringes. The impact of several experimental parameters onto the clock resonance and short-term fractional frequency stability, including the laser power, the cell temperature and the Ramsey sequence parameters, has been investigated. We observe and explain the existence of a slight dependence on laser power of the central Ramsey-CPT fringe line-width in the pulsed regime. We report also that the central fringe line-width is commonly narrower than the expected Ramsey linewidth given by 1/(2T R ), with T R the free-evolution time, for short values of T R . The clock demonstrates a short-term fractional frequency stability at the level of 2.3 × 10 −13 τ

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“…In the present study, comparable performances are obtained in the CW and the pulsed regime. Such conclusions were also reported in [33,34].…”

Section: Short-term Frequency Stabilitysupporting

confidence: 78%

A high-performance Raman-Ramsey Cs vapor cell atomic clock

Hafiz

Coget

Yun

et al. 2017

Journal of Applied Physics

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“…The pulsed optically pumped (POP) Rb frequency standard has demonstrated outstanding performances with a fractional frequency stability of 1.7 × 10 −13 τ −1/2 up to 1000 s and at the level of 10 −14 at 10 5 s 5 . Similar shortterm stabilities have been obtained with revisited doubleresonance schemes, pumped by lamp 6 or by laser 7 . An alternative approach is the development of atomic clocks based on coherent population trapping (CPT) 8,9 .…”

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confidence: 75%

Symmetric autobalanced Ramsey interrogation for high-performance coherent-population-trapping vapor-cell atomic clock

Hafiz

Coget

Petersen

et al. 2018

Applied Physics Letters

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We report a high-performance pulsed coherent population trapping (CPT) Cs cell atomic clock using the implementation of a symmetric auto-balanced Ramsey (SABR) interrogation sequence. The latter method is found to reduce the light-power induced frequency shift by an order of magnitude compared to a previous experiment using a simple auto-balanced Ramsey interrogation. The contribution of this shift to the clock frequency stability is now rejected in the 10 −16 range at 10 4 s averaging time. Additional tricks, including a compensation method to reduce the laser AM noise contribution and the generation of novel error signals for LO frequency and phase correction, have been implemented using a FPGA-based digital electronics board in order to improve the clock short-term stability by a factor 2. The Allan deviation of the SABR-CPT clock, extracted from a selected 3 × 10 4 s-long dataset, is 2 × 10 −13 τ −1/2 and averages down to the level of 2.5 × 10 −15 at 10 4 s. These results are encouraging to stimulate the development of hot cell CPT-based clocks for industrial, scientific, and instrumentation applications.

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“…We apply four methods, Franzen, CW-DR, Ramsey-DR and ODSE to measure the relaxation times in the buffergas 87 Rb vapor cell. The CW-DR and Ramsey-DR schemes were previously also used for analyses from a metrological point of view including the short-and long-term frequency stability of our Rb atomic clock [47]. Franzen, Ramsey-DR and ODSE methods operate in pulse mode.…”

Section: Characterization Methods and Resultsmentioning

confidence: 99%

Optically-detected spin-echo method for relaxation times measurements in a Rb atomic vapor

et al. 2017

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are relevant. Our ODSE method is inspired by classical nuclear magnetic resonance spin-echo method, combined with optical detection. In contrast to other existing methods, like continuous-wave double-resonance (CW-DR) and Ramsey-DR, principles of the ODSE method allow suppression of decoherence arising from the inhomogeneity of the static magnetic field across the vapor cell, thus enabling measurements of intrinsic relaxation rates, as properties of the cell alone. Our experimental result for the coherence relaxation time, specific for the clock transition, measured with the ODSE method is in good agreement with the theoretical prediction, and the ODSE results are validated by comparison to those obtained with Franzen, CW-DR and Ramsey-DR methods. The method is of interest for a wide variety of quantum optics experiments with optical signal readout.

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High performance vapour-cell frequency standards

Cited by 19 publications

References 22 publications

A high-performance Raman-Ramsey Cs vapor cell atomic clock

A high-performance Raman-Ramsey Cs vapor cell atomic clock

Symmetric autobalanced Ramsey interrogation for high-performance coherent-population-trapping vapor-cell atomic clock

Optically-detected spin-echo method for relaxation times measurements in a Rb atomic vapor

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