Low-temperature indium-bonded alkali vapor cell for chip-scale atomic clocks

Straessle, R.; Pellaton, M.; Affolderbach, C.; Pétremand, Y.; Briand, D.; Mileti, G.; Rooij, N. F. de

doi:10.1063/1.4789942

Cited by 31 publications

(20 citation statements)

References 30 publications

(37 reference statements)

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“…However, no drift of the clock resonance frequency could be shown. Straessle et al 18 discussed permeation of Nitrogen buffer gas into their Rb micro-cells to assess the hermiticity of micro-cells.…”

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confidence: 99%

“…Expected permeation rates, time constants, and initial linear drift of intrinsic cell frequency due to permeation are given, calculated for the microfabricated Cs-Ne cell under study (see below), using P in ¼ 60 mbar and the Ne pressure shift coefficient of 530 Hz/mbar. 26 Because K for permeation of both He and Ne through Si 27 is several orders of magnitude smaller than through borosilicate glass, 18,24 one can neglect the Si parts of the cell here and treat s of Eq. (2) applying to the cell's borofloat windows only.…”

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confidence: 99%

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Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

Abdullah

Affolderbach

Gruet

et al. 2015

Applied Physics Letters

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We report an aging study on micro-fabricated alkali vapor cells using neon as a buffer gas. An experimental atomic clock setup is used to measure the cell's intrinsic frequency, by recording the clock frequency shift at different light intensities and extrapolating to zero intensity. We find a drift of the cell's intrinsic frequency of (À5.2 6 0.6) Â 10 À11 /day and quantify deterministic variations in sources of clock frequency shifts due to the major physical effects to identify the most probable cause of the drift. The measured drift is one order of magnitude stronger than the total frequency variations expected from clock parameter variations and corresponds to a slow reduction of buffer gas pressure inside the cell, which is compatible with the hypothesis of loss of Ne gas from the cell due to its permeation through the cell windows. A negative drift on the intrinsic cell frequency is reproducible for another cell of the same type. Based on the Ne permeation model and the measured cell frequency drift, we determine the permeation constant of Ne through borosilicate glass as (5.7 6 0.7) Â 10 À22 m 2 s À1 Pa À1 at 81 C. We propose this method based on frequency metrology in an alkali vapor cell atomic clock setup based on coherent population trapping for measuring permeation constants of inert gases.

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confidence: 99%

Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

Abdullah

Affolderbach

Gruet

et al. 2015

Applied Physics Letters

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“…The evolved cell pressure P with time t can be derived from the internal and external pressures, as well as cell cavity volume V . The proportional relationship is given as [ 52 ]:

where L is the leak rate, P norm is the normalized pressure of 1 × 10 5 Pa and P ext is the external pressure of 1 atm. By solving Equation (2), the pressure can be expressed as:

where the initial pressure in the beginning is 10 −3 Pa depending on EVG510.…”

Section: Resultsmentioning

confidence: 99%

Microfabricated Vapor Cells with Reflective Sidewalls for Chip Scale Atomic Sensors

et al. 2018

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We investigate the architecture of microfabricated vapor cells with reflective sidewalls for applications in chip scale atomic sensors. The optical configuration in operation is suitable for both one-beam and two-beam (pump & probe) schemes. In the miniaturized vapor cells, the laser beam is reflected twice by the aluminum reflectors on the wet etched 54.7° sidewalls to prolong the optical length significantly, thus resulting in a return reflectance that is three times that of bare silicon sidewalls. To avoid limitations faced in the fabrication process, a simpler, more universal and less constrained fabrication process of microfabricated vapor cells for chip scale atomic sensors with uncompromised performance is implemented, which also decreases the fabrication costs and procedures. Characterization measurements show that with effective sidewall reflectors, mm3 level volume and feasible hermeticity, the elongated miniature vapor cells demonstrate a linear absorption contrast improvement by 10 times over the conventional micro-electro-mechanical system (MEMS) vapor cells at ~50 °C in the rubidium D1 absorption spectroscopy experiments. At the operating temperature of ~90 °C for chip scale atomic sensors, a 50% linear absorption contrast enhancement is obtained with the reflective cell architecture. This leads to a potential improvement in the clock stability and magnetometer sensitivity. Besides, the coherent population trapping spectroscopy is applied to characterize the microfabricated vacuum cells with 46.3 kHz linewidth in the through cell configuration, demonstrating the effectiveness in chip scale atomic sensors.

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“…MEMS alkali vapor cell technology, utilizing eutectic bonding, has been investigated for years [65,66,67,68,69,70]. According to this technology, the silicon–glass preform and glass cover, kept at a distance, are located in the vacuum chamber.…”

Section: Methods Of Mems Vapor Cell Fabricationmentioning

confidence: 99%

Technological Assessment of MEMS Alkali Vapor Cells for Atomic References

Knapkiewicz

2018

Micromachines

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This paper is a review that surveys work on the fabrication of miniature alkali vapor cells for miniature and chip-scale atomic clocks. Technology on microelectromechanical systems (MEMS) cells from the literature is described in detail. Special attention is paid to alkali atom introduction methods and sealing of the MEMS structure. Characteristics of each technology are collated and compared. The article’s rhetoric is guided by the proposed classification of MEMS cell fabrication methods and contains a historical outline of MEMS cell technology development.

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Low-temperature indium-bonded alkali vapor cell for chip-scale atomic clocks

Cited by 31 publications

References 30 publications

Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

Aging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks

Microfabricated Vapor Cells with Reflective Sidewalls for Chip Scale Atomic Sensors

Technological Assessment of MEMS Alkali Vapor Cells for Atomic References

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