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Affolderbach, Christoph

Nom
Affolderbach, Christoph
Affiliation principale
Fonction
Collaborateur scientifique
Email
christoph.affolderbach@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/478
_
0000-0003-0733-2991

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  • Publication
    Accès libre
    Imaging microwave and DC magnetic fields in a vapor-cell Rb atomic clock
    (2015-11-6)
    Affolderbach, Christoph 
    ;
    Du, Guan-Xiang
    ;
    Bandi Nagabhushan, Thejesh 
    ;
    Horsley, Andrew
    ;
    Treutlein, Philipp
    ;
    Mileti, Gaetano 
    We report on the experimental measurement of the dc and microwave magnetic field distributions inside a recently developed compact magnetron-type microwave cavity mounted inside the physics package of a high-performance vapor-cell atomic frequency standard. Images of the microwave field distribution with sub-100-μm lateral spatial resolution are obtained by pulsed optical-microwave Rabi measurements, using the Rb atoms inside the cell as field probes and detecting with a CCD camera. Asymmetries observed in the microwave field images can be attributed to the precise practical realization of the cavity and the Rb vapor cell. Similar spatially resolved images of the dc magnetic field distribution are obtained by Ramsey-type measurements. The T2 relaxation time in the Rb vapor cell is found to be position dependent and correlates with the gradient of the dc magnetic field. The presented method is highly useful for experimental in situ characterization of dc magnetic fields and resonant microwave structures, for atomic clocks or other atom-based sensors and instrumentation.
  • Publication
    Accès libre
    Experimental demonstration of a compact and high-performance laser-pumped rubidium gas cell atomic frequency standard
    (2006)
    Affolderbach, Christoph 
    ;
    Droz, F.
    ;
    Mileti, Gaetano 
    The authors present a compact high-performance laser-pumped Rubidium atomic frequency standard exploiting the advantages of laser optical pumping for improved stability. The clock is based on an industrial Rb clock with the lamp assembly removed and optically pumped by light from a compact frequency-stabilized laser head. The modification of the buffer gas filling in the clock resonance cell reduces instabilities on medium-term timescales arising from the ac Stark effect and temperature variations. The frequency stability of the demonstrator clock was measured to be better than 4×10-12Τ-1/2 up to 104 s, limited by the local oscillator (LO) quartz and RF loop electronics. Long-term drifts under atmosphere amount to 2-6×10-13/day only, comparable to or lower than that for lamp-pumped clocks under similar conditions. Typical signal contrasts lie at around 20%, corresponding to a shot-noise limit for the short-term stability of 2×10-13Τ-1/2. The results clearly demonstrate the feasibility of a laser-pumped Rb clock reaching <1×10-12Τ-1/2 in a compact device (< 2 L, 2 kg, 20 W), given the optimization of the implemented techniques. Compact high-performance clocks of this kind are of high interest for space applications such as telecommunications, science missions, and future generations of satellite navigation systems [GPS, global orbiting navigation satellite system (GLONASS), European satellite navigation system (GALILEO)].
  • Publication
    Accès libre
    Imaging Microwave and DC Magnetic Fields in a Vapor-Cell Rb Atomic Clock
    Affolderbach, Christoph 
    ;
    Du, Guan-Xiang
    ;
    Bandi, Thejesh
    ;
    Horsley, Andrew
    ;
    Treutlein, Philipp
    ;
    Mileti, Gaetano 
    We report on the experimental measurement of the dc and microwave magnetic field distributions inside a recently developed compact magnetron-type microwave cavity mounted inside the physics package of a high-performance vapor-cell atomic frequency standard. Images of the microwave field distribution with sub-100- μm lateral spatial resolution are obtained by pulsed optical-microwave Rabi measurements, using the Rb atoms inside the cell as field probes and detecting with a CCD camera. Asymmetries observed in the microwave field images can be attributed to the precise practical realization of the cavity and the Rb vapor cell. Similar spatially resolved images of the dc magnetic field distribution are obtained by Ramsey-type measurements. The T2 relaxation time in the Rb vapor cell is found to be position dependent and correlates with the gradient of the dc magnetic field. The presented method is highly useful for experimental in situ characterization of dc magnetic fields and resonant microwave structures, for atomic clocks or other atom-based sensors and instrumentation.