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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
    Métadonnées seulement
    Imaging the Static Magnetic Field Distribution in a Vapor Cell Atomic Clock
    (2015-4-12)
    Affolderbach, Christoph 
    ;
    Du, Guan-Xiang
    ;
    Bandi Nagabhushan, Thejesh 
    ;
    Horsley, Andrew
    ;
    Treutlein, Philipp
    ;
    Mileti, Gaetano 
    We use a Ramsey-type interaction scheme to measure spatially-resolved images of the static magnetic field (C-field) amplitude Bdc applied across the Rb cell in the physics package of a high-performance vapor-cell atomic clock. Low field variations of <; 0.5% are found across the recorded images, and Fourier analysis of the data indicates low variations of Bdc also along the direction of laser propagation. Images of the T2 relaxation time are obtained in a similar way, and show a distribution that correlates with the Bdc distribution. This indicates inhomogeneous dephasing due to C-field gradients, which also results in spatial variation of the T2 time for the clock transition.
  • Publication
    Accès libre
  • 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.
  • Publication
    Accès libre
    Imaging of relaxation times and microwave field strength in a microfabricated vapor cell
    Horsley, Andrew
    ;
    Du, Guan-Xiang
    ;
    Pellaton, Matthieu 
    ;
    Affolderbach, Christoph 
    ;
    Mileti, Gaetano 
    ;
    Treutlein, Philipp
    We present a characterization technique for atomic vapor cells, combining time-domain measurements with absorption imaging to obtain spatially resolved information on decay times, atomic diffusion, and coherent dynamics. The technique is used to characterize a 5-mm-diameter, 2-mm-thick microfabricated Rb vapor cell, with N2 buffer gas, placed inside a microwave cavity. Time-domain Franzen and Ramsey measurements are used to produce high-resolution images of the population (T1) and coherence (T2) lifetimes in the cell, while Rabi measurements yield images of the σ -, π, and σ + components of the applied microwave magnetic field. For a cell temperature of 90∘C, the T1 times across the cell center are found to be a roughly uniform 265μs, while the T2 times peak at around 350μs. We observe a “skin” of reduced T1 and T2 times around the edge of the cell due to the depolarization of Rb after collisions with the silicon cell walls. Our observations suggest that these collisions are far from being 100% depolarizing, consistent with earlier observations made with Na and glass walls. Images of the microwave magnetic field reveal regions of optimal field homogeneity, and thus coherence. Our technique is useful for vapor cell characterization in atomic clocks, atomic sensors, and quantum information experiments.