The Passive Optically Pumped Rb Frequency Standard: the Laser Approach

Vanier,; Mandache,

doi:10.1109/freq.2007.4319296

Cited by 7 publications

(7 citation statements)

References 20 publications

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“…The output resonance signal, whose line-width is ultimately limited by the CPT coherence lifetime, can then be used as a narrow frequency discriminator towards the development of an atomic frequency standard. In a CPT-based clock, unlike the traditional double-resonance Rb clock [15], the microwave signal used to probe the hyperfine frequency is directly optically carried allowing to remove the microwave cavity and potentially to shrink significantly the clock dimensions.…”

Section: Introductionmentioning

confidence: 99%

High-Performance Coherent Population Trapping Clock with Polarization Modulation

et al. 2017

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We demonstrate a vapor cell atomic clock prototype based on continuous-wave (CW) interrogation and double-modulation coherent population trapping (DM-CPT) technique. The DM-CPT technique uses a synchronous modulation of polarization and relative phase of a bi-chromatic laser beam in order to increase the number of atoms trapped in a dark state, i.e. a non-absorbing state. The narrow resonance, observed in transmission of a Cs vapor cell, is used as a narrow frequency discriminator in an atomic clock. A detailed characterization of the CPT resonance versus numerous parameters is reported. A short-term frequency stability of 3.2 × 10 −13 τ −1/2 up to 100 s averaging time is measured. These performances are more than one order of magnitude better than industrial Rb clocks and comparable to those of best laboratory-prototype vapor cell clocks. The noise budget analysis shows that the short and mid-term frequency stability is mainly limited by the power fluctuations of the microwave used to generate the bi-chromatic laser. These preliminary results demonstrate that the DM-CPT technique is well-suited for the development of a high-performance atomic clock, with potential compact and robust setup due to its linear architecture. This clock could find future applications in industry, telecommunications, instrumentation or global navigation satellite systems.

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Section: Introductionmentioning

confidence: 99%

High-Performance Coherent Population Trapping Clock with Polarization Modulation

et al. 2017

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“…The long-term frequency stability of the clock is usually dictated by the frequency shifts caused due to a number of factors such as laser frequency drift, laser intensity noise, variations in cell temperature, buffer gas pressure, external magnetic field, etc. [11,12]. A fundamental limit on the long-term stability is imposed by the light shift.…”

Section: Introductionmentioning

confidence: 99%

“…In many situations, it can be accurately calculated for predicting the performance of the clock. For example, in the case of an optically-pumped atomic clock, light shift-related frequency instabilities can be comprehensively modeled by investigating laser interaction with a two-level atomic system [11,13]. Similarly, light shift in a CPT clock can also be modeled using a three-level system interacting with the continuous bichromatic laser fields [12,[14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Computational studies of light shift in a Raman–Ramsey interference-based atomic clock

Pati

Warren

et al. 2015

J. Opt. Soc. Am. B

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Determining light shift in Raman-Ramsey interference is important for the development of atomic frequency standards based on a vapor cell. We have accurately calculated light shift in Raman-Ramsey interference using the densitymatrix equations for a three-level system without invoking the adiabatic approximation. Specifically, phase shifts associated with coherent density-matrix terms are studied as they are relevant to the detection of Raman-Ramsey interference in transmission (or absorption) through the medium. For the single-velocity case, the numerically computed results are compared with the analytical results obtained using the adiabatic approximation. The result shows light shift suppression in conformity with the closed-form analytic solutions. The computational studies have also been extended to investigate Raman-Ramsey interference for a Doppler-broadened vapor medium. Importantly, a velocity-induced frequency shift is found at the fringe center as an additional source of frequency error for a vapor cell Raman clock.

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“…A great deal of work has been devoted to the search for alternatives to the usual pumping scheme using a discharge lamp and a filter cell, and for improvement of the short-term frequency stability. The replacement of the lamp by a diode laser gave great hope [7,8,9]. Very recently noteworthy results were obtained by Bandi et al [10] with short term stability better than 3×10 -13 τ -1/2 .…”

Section: Introductionmentioning

confidence: 99%

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

Kozlova

Danet

Guérandel

et al. 2014

IEEE Trans. Instrum. Meas.

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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 D 1 line transmission, using a double Λ 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.

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The Passive Optically Pumped Rb Frequency Standard: the Laser Approach

Cited by 7 publications

References 20 publications

High-Performance Coherent Population Trapping Clock with Polarization Modulation

High-Performance Coherent Population Trapping Clock with Polarization Modulation

Computational studies of light shift in a Raman–Ramsey interference-based atomic clock

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

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