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FN Rubidium-Precision double resonance spectroscopy and metrology
Durant ces dernières années, un progrès notable a eu lieu dans le domaine des horloges atomiques à cellule compactes (2-10 litres) et haute performances (stabilité reléative de ≈ 1-14 à un jour), pour des applications telles que la navigation par satellite (GALILEO, GPS, etc.). En parallèle, la miniaturisation extrème de ce type d'étalons de fréquence a aussi constitué un axe de recherche très actif.
Notre projet a l'objectif de poursuivre ces investigations en suivant des approches spectroscopiques originales afin de mieux comprendre les phénomènes physiques se déroulant dans la cellule de résonance et ainsi établir les bases pour une nouvelle génération d'horloges atomiques de haute performance et/ou miniatures.
Double-resonance spectroscopy in Rubidium vapour-cells for high performance and miniature atomic clocks
2017-2-16, Gharavipour, Mohammadreza, Affolderbach, Christoph, Mileti, Gaetano, Kang, S
We report our studies on using microwave-optical double-resonance (DR) spectroscopy for a high-performance Rb vapour-cell atomic clock in view of future industrial applications. The clock physics package is very compact with a total volume of only 0.8 dm3. It contains a recently in-house developed magnetron-type cavity and a Rb vapour cell. A homed-made frequency-stabilized laser system with an integrated acousto-optical-modulator (AOM) – for switching and controlling the light output power– is used as an optical source in a laser head (LH). The LH has the overall volume of 2.5 dm3 including the laser diode, optical elements, AOM and electronics. In our Rb atomic clock two schemes of continuous-wave DR and Ramsey-DR schemes are used, where the latter one strongly reduces the light-shift effect by separation of the interaction of light and microwave. Applications of the DR clock approach to more radically miniaturized atomic clocks are discussed.
Barometric Effect in Vapor-Cell Atomic Clocks
2018-6-4, Moreno, William, Pellaton, Matthieu, Affolderbach, Christoph, Mileti, Gaetano
Vapor-cell atomic clocks are compact and high-performance frequency references employed in various appli-cations ranging from telecommunication to global positioningsystems. Environmental sensitivities are often the main sourcesof long-term instabilities of the clock frequency. Among thesesensitivities, the environmental pressure shift describes the clockfrequency change with respect to the environmental pressurevariations. We report here on our theoretical and experimentalanalysis of the environmental pressure shift on rubidium atomicfrequency standards (RAFSs) operated under open atmosphere.By using an unsealed high-performance laser-pumped rubidiumstandard, we demonstrate that the deformation of the vapor-cell volume induced by the environmental pressure changes(i.e., barometric effect) is the dominant environmental pressureshift in a standard laboratory environment. An experimentalbarometric coefficient of 8.2×10−14/hPa is derived, in goodagreement with theory and with previously reported measure-ments of frequency shifts of RAFS operated when transiting tovacuum.