In: Applied Physics B, 2009, vol. 96, no. 4, p. 763-772
We have manufactured more than 250 nominally identical paraffin-coated Cs vapor cells (28 mm inner diameter bulbs) for multi-channel atomic magnetometer applications. We describe our dedicated cell characterization apparatus. For each cell we have determined the intrinsic longitudinal, Γ ₀₁, and transverse, Γ ₀₂, relaxation rates. Our best cell shows Γ...
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In: Nuclear Instruments and Methods in Physics Research Section A, 2009///doi: 10.1016/j.nima.2009.07.079
High precision mapping of weak magnetic fields is of interest for several branches of pure and applied research. This paper presents a resume of the progress made at Fribourg in adapting laboratory style laser-pumped optical Cs magnetometers to multisensor field mapping problems. Progress has been made in sensor head design and manufacture, laser beam splitting and control, and signal treatment...
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In: Physics Reports, 2008, vol. 469, no. 1, p. 1-57
The studies of defects formed by impurity particles (atoms, molecules, exciplexes, clusters, free electrons, and positive ions) embedded in liquid and solid ⁴He are reviewed. The properties of free electrons and neutral particles in condensed helium are described by the electron (atomic) bubble model, whereas for the positive ions a snowball structure is considered. We compare the properties of...
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In: Physical Review A, 2008, vol. 78, p. 032501
We present time-resolved measurements of the laser-induced fluorescence from Cs atoms and Cs*HeN exciplexes in a solid ⁴He matrix. The linear Cs*He₌₂ exciplex is strongly quenched by a radiationless transformation into a ring-shaped Cs*HeN=6,7 exciplex, which decays radiatively with a lifetime of 88±2 ns. The analysis...
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In: The European Physical Journal D, 2008, vol. 46, no. 1, p. 9-14
We present the first experimental study of time-resolved fluorescence from laser-excited Cs(6P1/2) atoms isolated in a solid ⁴He matrix. The results are compared to the predictions of the bubble model including the interaction of the atomic dipole with its radiation reflected at the bubble interface. Our results show that in liquid He as well as in the body-centered cubic (bcc)...
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In: Physical Review A, 2008, vol. 77, no. 12, p. 012502
We give a detailed account on our semiempirical calculations of the forbidden electric tensor polarizability α₂⁽³⁾ of the ground state of free Cs atoms and of Cs atoms implanted in a solid 4He matrix. The results are compared with measurements of α₂⁽³⁾ in the free atoms [Europhys. Lett. 76, 1074 (2006)] and in He-trapped atoms [Phys. Rev. A 75, 042505 (2007)]. Features with...
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In: Nature Physics, 2007, vol. 3, no. <, p. 786 - 789
The modification of melting temperatures and pressures by dissolved impurities is well known in classical fluids. However, to our knowledge such effects have never been studied in quantum solids because of the difficulties in introducing impurities into such crystals that exist only at cryogenic temperatures, and, in the case of ⁴He, at pressures exceeding 25 bar. Here, we present an effect...
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In: Physical Review A, 2007, vol. 76, no. 2, p. 022502
We present a systematic experimental study of the absorption and fluorescence spectra of the 6S1/2-6P1/2 transition in Cs atoms isolated in solid ⁴He matrices. The bubble model developed earlier for alkali-metal atoms in liquid He is revised and applied to the present system. The analysis of the dependencies of absorption and fluorescence wavelengths on He...
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In: Physical Review A, 2007, p. 042505
We have measured the electric tensor polarizabilities of the hyperfine levels of Cs atoms embedded in a body-centered cubic ⁴He crystal. The polarizabilities are inferred from the shift of optically detected magnetic resonance lines in each hyperfine level induced by static electric fields up to 50 kV/cm. We recorded the magnetic resonances both by scanning the rf frequency and in a...
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In: Europhysics Letters, 2006, vol. 76, no. 6, p. 1074-1080
We present a new theoretical analysis of the strongly suppressed F- and M-dependent Stark shifts of the Cs ground-state hyperfine structure. Our treatment uses third-order perturbation theory including off-diagonal hyperfine interactions not considered in earlier treatments. A numerical evaluation of the perturbation sum using bound states up to n = 200 yields ground-state...
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