Ramsey-coherent population trapping Cs atomic clock based on lin∥lin optical pumping with dispersion detection*

Cheng, Pengfei; Zhang, J. W.; Wang, Lijun

doi:10.1088/1674-1056/28/7/070601

Cited by 7 publications

(5 citation statements)

References 25 publications

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“…However, the two-laser system in both schemes hinders compact and robust applications. External modulators, such as acousto-optic modulator (AOM) or electro-optic modulator, are usually employed in push-pull CPT [16,17], lin//lin CPT [18][19][20], double-modulation (DM) CPT [21,22], and lin⊥lin CPT [23]. Excellent short-term frequency stabilities at the level of 1-3 × 10 -13 τ -1/2 have been typically observed [3][4][5][6].…”

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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“…Ramsey spectroscopy, employing the method of separated oscillating fields, enables precise measurements of atomic and molecular resonance [1]. This widely used spectroscopy has been successfully applied in a variety of quantum sensing including the atomic frequency standards [2][3][4], atomic inertial sensors and quantum magnetometers [5][6][7][8][9]. In a typical Ramsey sequence, atoms are interrogated with two pulses separated by a free-evolution time T. While the fringe width of Ramsey spectroscopy, ∆ = 1/2T, remains unaffected by the interrogation pulses, the electromagnetic field perturbation * Authors to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Reduction of light shifts in a cold-atom CPT clock

Li,

Ma,

et al. 2024

J. Phys. B: At. Mol. Opt. Phys.

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Light shifts induced during atom-light interactions significantly affect the medium- and long-term frequency stability of atomic clocks. Here, we employ composite laser pulse sequences to mitigate interrogation-induced light shifts in a cold-atom coherent-population-trapping clock. We obtain the anti-symmetry error signal via modulating the local oscillator phase in the free-evolution time of Ramsey interferometry. Utilizing this signal, we employ two feedback loops to simultaneously eliminate light shifts and stabilize the clock frequency using the auto-balanced Ramsey spectroscopy scheme. Our experimental results demonstrate that this approach can reduce the clock frequency's sensitivity to variations in light shifts by implementing four Ramsey sub-sequences. Furthermore, we show that the auto-balanced Ramsey spectroscopy scheme enhances the long-term frequency stability of the atomic clock when the averaging time $\tau>5000$ s.

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“…However, the two-laser system in both schemes hinders compact and robust applications. External modulators, such as acousto-optic modulator (AOM) or electro-optic modulator, are usually employed in push-pull CPT [21,22], lin//lin CPT [23][24][25], doublemodulation (DM) CPT [26,27], and lin⊥lin CPT [28]. Excellent short-term frequency stabilities at the level of 1-3 × 10 −13 τ −1/2 have been typically observed [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

High-performance coherent population trapping atomic clock with direct-modulation distributed Bragg reflector laser

Yun¹,

Li²,

Hao³

et al. 2021

Metrologia

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The coherent population trapping (CPT) atomic clock is very promising for use in next-generation spaceborne applications owing to its compactness and high performance. In this paper, we propose and implement a CPT atomic clock based on the direct modulation of a large-modulation-bandwidth and narrow-linewidth distributed Bragg reflector laser, which replaces the usually used external bulk modulator in high-performance CPT clocks. Our method retains the high performance while significantly reducing the clock size. Using this highly compact bichromatic light source and simplest CPT configuration, in which a circularly polarized bichromatic laser interrogates the 87 Rb atom system, a CPT signal of clock transition with a narrow linewidth and high contrast is observed. We then lock the local oscillator frequency to the CPT resonance and demonstrate an encouraging short-term frequency stability of 3.6 × 10 −13 τ −1/2 (4 s τ 200 s). We attribute it to the ultralow laser frequency and intensity noise as well as to the high-quality-factor CPT signal. This study can pave the way for the development of compact high-performance CPT clocks based on our scheme.

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Ramsey-coherent population trapping Cs atomic clock based on lin∥lin optical pumping with dispersion detection*

Cited by 7 publications

References 25 publications

High-Performance Coherent Population Trapping Clock with Polarization Modulation

High-Performance Coherent Population Trapping Clock with Polarization Modulation

Reduction of light shifts in a cold-atom CPT clock

High-performance coherent population trapping atomic clock with direct-modulation distributed Bragg reflector laser

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