Improvement in medium long-term frequency stability of the integrating sphere cold atom clock

Liu, Peng; Cheng, Huadong; Meng, Yaobin; Wan, Jinyin; Liu, Xiao; Wang, Xiumei; Wang, Yaning; Liu, Liang

doi:10.1364/josab.33.001439

Cited by 10 publications

(4 citation statements)

References 16 publications

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“…Cavity pulling is assumed to give the main contribution to the medium-long term stability of compact cold atom clocks as well [32]. This is mainly due to the fact that in compact devices, differently from atomic fountains, the whole clock operation takes place inside the microwave cavity.…”

Section: Discussionmentioning

confidence: 99%

Reducing Cavity-Pulling Shift in Ramsey-Operated Compact Clocks

Gozzelino

Micalizio

Levi

et al. 2018

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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We describe a method to stabilize the amplitude of the interrogating microwave field in compact atomic clocks working in a Ramsey approach. In this technique, we take advantage of the pulsed regime to use the atoms themselves as microwave amplitude discriminators. Specifically, in addition to the dependence on the microwave detuning, the atomic signal after the Ramsey interrogation acquires a dependence on the microwave pulse area (amplitude times duration) that can be exploited to implement an active stabilization of the microwave field amplitude, in a similar way in which the Ramsey clock signal is used to lock the local oscillator frequency to the atomic reference. The stabilization allows us to reduce the microwave field-amplitude fluctuations, which in turn impact the clock frequency through cavity pulling. The proposed technique has shown to be effective to improve our clock frequency stability on medium and long term. We demonstrate the method for a vapor-cell clock working with a hot sample of atoms, but it can be extended to cold-atom compact clocks.

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Section: Discussionmentioning

confidence: 99%

Reducing Cavity-Pulling Shift in Ramsey-Operated Compact Clocks

Gozzelino

Micalizio

Levi

et al. 2018

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…This cooling technique allows the conception of compact and robust sources of cold atoms for spectroscopy applications or sensors. Some high performances atomic clocks based on ILC are already in development [15][16][17][18].…”

Section: Ilc Of An Atomic Vapor Was First Demonstrated Bymentioning

confidence: 99%

Isotropic light versus six-beam molasses for Doppler cooling of atoms from background vapor: Theoretical comparison

2017

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We present a 3D theoretical comparison between the radiation-pressure forces exerted on an atom in an isotropic light cooling scheme and in a six-beam molasses. We demonstrate that, in the case of a background vapor where all the space directions of the atomic motion have to be considered, the mean cooling rate is equal in both configurations. Nevertheless, we also point out what mainly differentiates the two cooling techniques: the force component orthogonal to the atomic motion. If this transverse force is always null in the isotropic light case, it can exceed the radiation-pressureforce longitudinal component in the six-beam molasses configuration for high atomic velocities, hence reducing the velocity capture range.

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“…Meanwhile, isotropic laser cooling (ILC) in the form of cold atoms enclosed in an environment of diffuse reflection light [25][26][27][28][29] has found critical applications in microwave atomic clocks, spectroscopic studies and quantum sensors [30][31][32][33][34][35] due to its unique characteristics of compactness and robustness [32,34]. To ensure the quality of the diffuse optical field of ILC, the enclosure of the diffuse reflection surface around the atoms needs to cover nearly the entire 4π solid angle.…”

mentioning

confidence: 99%

Nearly nondestructive thermometry of labeled cold atoms and application to isotropic laser cooling

Wang,

Sun,

Cheng

et al. 2020

Preprint

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We have designed and implemented a straightforward method to deterministically measure the temperature of the selected segment of a cold atom ensemble, and we have also developed an upgrade in the form of nondestructive thermometry. The essence is to monitor the thermal expansion of the targeted cold atoms after labeling them through manipulating the internal states, and the nondestructive property relies upon the nearly lossless detection via driving a cycling transition. For cold atoms subject to isotropic laser cooling, this method has the unique capability of addressing only the atoms on the optical detection axis within the enclosure, which is exactly the part we care about in major applications such as atomic clock or quantum sensing. Furthermore, our results confirm the sub-Doppler cooling features in isotropic laser cooling, and we have investigated the relevant cooling properties. Meanwhile, we have applied the recently developed optical configuration with the cooling laser injection in the form of hollow beams, which helps to enhance the cooling performance and accumulate more cold atoms in the central regions.

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Improvement in medium long-term frequency stability of the integrating sphere cold atom clock

Cited by 10 publications

References 16 publications

Reducing Cavity-Pulling Shift in Ramsey-Operated Compact Clocks

Reducing Cavity-Pulling Shift in Ramsey-Operated Compact Clocks

Isotropic light versus six-beam molasses for Doppler cooling of atoms from background vapor: Theoretical comparison

Nearly nondestructive thermometry of labeled cold atoms and application to isotropic laser cooling

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