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Affolderbach, Christoph
Nom
Affolderbach, Christoph
Affiliation principale
Fonction
Collaborateur scientifique
Email
christoph.affolderbach@unine.ch
Identifiants
Résultat de la recherche
Voici les éléments 1 - 5 sur 5
- PublicationMétadonnées seulementOptically-detected spin-echo method for relaxation times measurements in a Rb atomic vapor(2017-6-26)
; ; ; ; - PublicationMétadonnées seulementHigh performance vapour-cell frequency standards(: Journal of Physics: Conference Series 723, 2015-10-27)
; ; ; ; ; ; We report our investigations on a compact high-performance rubidium (Rb) vapour-cell clock based on microwave-optical double-resonance (DR). These studies are done in both DR continuous-wave (CW) and Ramsey schemes using the same Physics Package (PP), with the same Rb vapour cell and a magnetron-type cavity with only 45 cm3 external volume. In the CW-DR scheme, we demonstrate a DR signal with a contrast of 26% and a linewidth of 334 Hz; in Ramsey-DR mode Ramsey signals with higher contrast up to 35% and a linewidth of 160 Hz have been demonstrated. Short-term stabilities of 1.4×10^-13 τ^-1/2 and 2.4×10^-13 τ^-1/2 are measured for CW-DR and Ramsey-DR schemes, respectively. In the Ramsey-DR operation, thanks to the separation of light and microwave interactions in time, the light-shift effect has been suppressed which allows improving the long-term clock stability as compared to CW-DR operation. Implementations in miniature atomic clocks are considered. - PublicationMétadonnées seulementAging studies on micro-fabricated alkali buffer-gas cells for miniature atomic clocks(2015-4-22)
; ; 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 (−5.2 ± 0.6) × 10−11/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 ± 0.7) × 10−22 m2 s−1 Pa−1 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. The authors gratefully acknowledge fruitful discussions with M. Pellaton (Université de Neuchâtel) and S. Karlen (CSEM SA, Neuchâtel, Switzerland) on buffer gas permeation, Y. Pétremand (CSEM) for providing the vapor cells, and D. Varidel (Université de Neuchâtel) for support with the H-maser reference. This work was funded by the Swiss National Science Foundation (FNS) and co-financed by the Swiss Commission for Technology and Innovation (CTI) - PublicationMétadonnées seulementPulsed Optically Pumped Rubidium Clock With High Frequency-Stability Performance(2012-4-3)
; In this paper, we present the performance of a vapor-cell rubidium frequency standard working in the pulsed regime, in which the clock signal is represented by a Ramsey pattern observed on an optically detected laser absorption signal. The main experimental results agree with previously reported theoretical predictions. In particular, we measured a relative frequency stability of σy(τ) ≈ 1.6 × 10^−13 τ^−1/2 for integration times, τ, up to 200 s, which represents a record in short-term stability for a vapor-cell clock. We also discuss the most important physical phenomena that contribute to this result. - PublicationMétadonnées seulementOptimizing a high-stability cw laser-pumped Rubidium gas-cell frequency standard(USA: Maleki Lute, 2009)
; ; ; We report on our development of a compact and high-performance laser-pumped Rubidium atomic frequency standard. The clock design is based on optical-microwave double-resonance using cw optical pumping, and a physical realization as simple as possible. Main development goals are a short-term instability of ≤ 6 × 10-13 τ-1/2 and a flicker floor of ≤ 1 × 10-14 up to one day. Here we discuss our approaches for controlling the clock's main physical parameters in view of optimized frequency stability.