Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1705.01379

Phase-shift in vapor cell and compact cold-atom frequency standards

Aldo Godone, Salvatore Micalizio

Published May 3, 2017• 0 citations
arXivHTMLPDF

Abstract

We report on a theoretical analysis of the phase-shift in compact atomic clocks working either with cold or thermal atoms. It is well known that in a microwave cavity with electromagnetic losses, a traveling wave adds to the standing wave of a given resonant mode. We calculate the spatial varying phase related to this travelling wave for two geometries of interest in clock applications, the cylindrical cavity and the spherical cavity. Due to their motion, the atoms probe different regions of the cavity and then experience different phases of the interrogating microwave field. We show that this combination of atomic motion and spatial changing phase results in a phase-shift of the clock frequency, well known in primary frequency standards, that can affect the metrological performances also of vapor cell and compact cold-atom clocks. In the latter case, we evaluate the phase-shift for a space clock and a ground clock.

DOI
10.48550/arxiv.1705.01379

Related papers

Study of field misalignment in a cavity used for atomic clock applications

Anton E. Ivanov, C. Affolderbach, G. Mileti +1 more

In vapor cell atomic clocks the atom-field interaction is typically obtained inside a microwave cavity resonator in which the microwave driving field together with a static magnetic field and an optical field are applied to excite the atoms. These fields are generally well-controlled, mutually aligned to a common quantization axis. Since the exploited atomic transition is sensitive to any potential axis misalignment, the performance of the clock can also be affected. We study the effect of such misalignment for the case of a cylindrical cavity used in vapor-cell atomic clocks, taking into account the misalignments of the optical detection field and the static magnetic field required for the atomic transition. Both the geometry of the cavity and the factors contributing to losses can play role in the degradation of the signal and are taken into account in the misalignment problem discussed.

URSI International Symposium on Electromagnetic Theory•Aug 1, 2016•1 citation

A frequency shift compensation method for light shift and vapor-cell temperature shift in atomic clocks

Dou Li, Kangqi Liu, Linzhen Zhao +1 more

Light shift and vapor-cell temperature shift are the two most significant factors dominating the long-term instability of compact atomic clocks. Due to the different physical mechanisms, there is not yet a solution that can effectively suppress the frequency shifts induced by these two effects. Here, we propose a 'resonance-offset' locking approach that compensates for the two physical frequency shifts. In this approach, the additional offset locking shift can effectively counteract the atomic resonance shifts arising from changes in vapor-cell temperature and light power, reducing the net impact on the clock's frequency to nearly zero. We have demonstrated this strategy on the 778 nm Rubidium two-photon optical frequency standard, successfully compensating for light shift and cell-temperature shift, respectively. This general method is particularly appealing for compact vapor-cell microwave and optical atomic clocks designed for the excellent stability rather than accuracy.

arXiv:2405.14281•May 23, 2024•0 citations

A Movable-Cavity Cold Atom Space Clock

Bian Fenggang, Rong Wei, Haifeng Jiang +1 more

We present an experimental scheme of a cold atom space clock with a movable cavity. By using a single microwave cavity, we find that the clock has a significant advantage, i.e. the longitudinal cavity phase shift is eliminated. A theoretical analysis has been carried out in terms of the relation between the atomic transition probability and the velocity of the moving cavity by taking into account the velocity distribution of cold atoms. The requirements for the microwave power and its stability for atomic π/2 excitation at different moving velocities of the cavity lead to the determination of the proper working parameters of the rubidium clock in frequency accuracy 10 −17 . Finally, the mechanical stability for the scheme is analysed and the ways of solving the possible mechanical instability of the device are proposed.

Chinese Physics Letters•Jun 16, 2005•1 citation

Development of compact laser cooled atomic frequency standards

T. Zanon-Willette, S. Trémine, Stéphane Guérandel +4 more

Two projects of compact cold atom clocks are currently developed: a clock with atoms directly cooled in the microwave cavity and a clock based on coherent population trapping. For each device, different interrogation and detection schemes are evaluated and reported

Conference on Precision Electromagnetic Measurements•Jun 1, 2004•1 citation

Distortion of Rabi oscillations in a compact cold-atom clock

Xinchuan Ouyang, Bowen Yang, Qingqing Hu +4 more

We report on experimental measurements and theoretical calculations of Rabi oscillation distortion during rubidium clock transition in a compact cold-atom clock. The distortion of the Rabi oscillations of the clock transition caused by the magnetically sensitive transitions between magnetic sublevels is related to the duration and amplitude of the microwave pulse, the density distribution of cold atoms, and the biased magnetic field inside the microwave cavity. The theoretical calculations agreed well with the experimental results. The Rabi oscillation measurements are beneficial for determining the optimal parameters of a cold-atom clock and identifying the uniformity of the microwave field inside the cavity. This measurement can be extended to the atomic fountain clock and the vapor-cell atomic clock.

Physical Review A•Apr 26, 2021•4 citations

Loaded Microwave Cavity for Compact Vapor-Cell Clocks

Michele Gozzelino, Salvatore Micalizio, Claudio Eligio Calosso +3 more

Vapor-cell devices based on microwave interrogation provide a stable frequency reference with a compact and robust setup. Further miniaturization must focus on optimizing the physics package, containing the microwave cavity and atomic reservoir. In this article, we present a compact cavity-cell assembly based on a dielectric-loaded cylindrical resonator. The loaded cavity resonating at 6.83 GHz has an external volume of only 35 cm3and accommodates a vapor cell with 0.9-cm3inner volume. The proposed design aims at strongly reducing the core of the atomic clock, maintaining, at the same time, high-performing short-term stability ($\sigma _{y}{(}\tau {)} \leq {5}\times {10}^{-{13}} \,\tau ^{-{1}/{2}}$ standard Allan deviation). The proposed structure is characterized in terms of microwave field uniformity and atom-field coupling with the aid of finite-element calculations. The thermal sensitivity is also analyzed and experimentally characterized. We present preliminary spectroscopy results by integrating the compact cavity within a rubidium clock setup based on the pulsed optically pumping technique. The obtained clock signals are compatible with the targeted performances. The loaded-cavity approach is, thus, a viable design option for miniaturized microwave clocks.

arXiv:2005.10159•IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control•Jul 23, 2020•9 citations
We report on a theoretical analysis of the phase-shift in compact atomic clocks working either with cold or thermal atoms. It is well known that in a microwave cavity with electromagnetic losses, a traveling wave adds to the standing wave of a given resonant mode. We calculate the spatial varying phase related to this travelling wave for two geometries of interest in clock applications, the cylindrical cavity and the spherical cavity. Due to their motion, the atoms probe different regions of the cavity and then experience different phases of the interrogating microwave field. We show that this combination of atomic motion and spatial changing phase results in a phase-shift of the clock frequency, well known in primary frequency standards, that can affect the metrological performances also of vapor cell and compact cold-atom clocks. In the latter case, we evaluate the phase-shift for a space clock and a ground clock.
In vapor cell atomic clocks the atom-field interaction is typically obtained inside a microwave cavity resonator in which the microwave driving field together with a static magnetic field and an optical field are applied to excite the atoms. These fields are generally well-controlled, mutually aligned to a common quantization axis. Since the exploited atomic transition is sensitive to any potential axis misalignment, the performance of the clock can also be affected. We study the effect of such misalignment for the case of a cylindrical cavity used in vapor-cell atomic clocks, taking into account the misalignments of the optical detection field and the static magnetic field required for the atomic transition. Both the geometry of the cavity and the factors contributing to losses can play role in the degradation of the signal and are taken into account in the misalignment problem discussed.
Light shift and vapor-cell temperature shift are the two most significant factors dominating the long-term instability of compact atomic clocks. Due to the different physical mechanisms, there is not yet a solution that can effectively suppress the frequency shifts induced by these two effects. Here, we propose a 'resonance-offset' locking approach that compensates for the two physical frequency shifts. In this approach, the additional offset locking shift can effectively counteract the atomic resonance shifts arising from changes in vapor-cell temperature and light power, reducing the net impact on the clock's frequency to nearly zero. We have demonstrated this strategy on the 778 nm Rubidium two-photon optical frequency standard, successfully compensating for light shift and cell-temperature shift, respectively. This general method is particularly appealing for compact vapor-cell microwave and optical atomic clocks designed for the excellent stability rather than accuracy.
We present an experimental scheme of a cold atom space clock with a movable cavity. By using a single microwave cavity, we find that the clock has a significant advantage, i.e. the longitudinal cavity phase shift is eliminated. A theoretical analysis has been carried out in terms of the relation between the atomic transition probability and the velocity of the moving cavity by taking into account the velocity distribution of cold atoms. The requirements for the microwave power and its stability for atomic π/2 excitation at different moving velocities of the cavity lead to the determination of the proper working parameters of the rubidium clock in frequency accuracy 10 −17 . Finally, the mechanical stability for the scheme is analysed and the ways of solving the possible mechanical instability of the device are proposed.
We report on experimental measurements and theoretical calculations of Rabi oscillation distortion during rubidium clock transition in a compact cold-atom clock. The distortion of the Rabi oscillations of the clock transition caused by the magnetically sensitive transitions between magnetic sublevels is related to the duration and amplitude of the microwave pulse, the density distribution of cold atoms, and the biased magnetic field inside the microwave cavity. The theoretical calculations agreed well with the experimental results. The Rabi oscillation measurements are beneficial for determining the optimal parameters of a cold-atom clock and identifying the uniformity of the microwave field inside the cavity. This measurement can be extended to the atomic fountain clock and the vapor-cell atomic clock.
Vapor-cell devices based on microwave interrogation provide a stable frequency reference with a compact and robust setup. Further miniaturization must focus on optimizing the physics package, containing the microwave cavity and atomic reservoir. In this article, we present a compact cavity-cell assembly based on a dielectric-loaded cylindrical resonator. The loaded cavity resonating at 6.83 GHz has an external volume of only 35 cm3and accommodates a vapor cell with 0.9-cm3inner volume. The proposed design aims at strongly reducing the core of the atomic clock, maintaining, at the same time, high-performing short-term stability (σy(τ)≤5×10−13 τ−1/2\sigma _{y}{(}\tau {)} \leq {5}\times {10}^{-{13}} \,\tau ^{-{1}/{2}}σy​(τ)≤5×10−13τ−1/2 standard Allan deviation). The proposed structure is characterized in terms of microwave field uniformity and atom-field coupling with the aid of finite-element calculations. The thermal sensitivity is also analyzed and experimentally characterized. We present preliminary spectroscopy results by integrating the compact cavity within a rubidium clock setup based on the pulsed optically pumping technique. The obtained clock signals are compatible with the targeted performances. The loaded-cavity approach is, thus, a viable design option for miniaturized microwave clocks.