4,731 research outputs found

    Dark resonances as a probe for the motional state of a single ion

    Full text link
    Single, rf-trapped ions find various applications ranging from metrology to quantum computation. High-resolution interrogation of an extremely weak transition under best observation conditions requires an ion almost at rest. To avoid line-broadening effects such as the second order Doppler effect or rf heating in the absence of laser cooling, excess micromotion has to be eliminated as far as possible. In this work the motional state of a confined three-level ion is probed, taking advantage of the high sensitivity of observed dark resonances to the trapped ion's velocity. Excess micromotion is controlled by monitoring the dark resonance contrast with varying laser beam geometry. The influence of different parameters such as the cooling laser intensity has been investigated experimentally and numerically

    Detection Techniques for Trapped Ions

    Full text link
    Various techniques are used to detect the presence of charged particles stored in electromagnetic traps, their energy, their mass, or their internal states. Detection methods can rely on the variation of the number of trapped particles (destructive methods) or the use of the ion's interaction with electromagnetic radiation as a non-destructive tool to probe the trapped particles. This review gives an introduction into various methods, discussing the basic mode of operation completed by the description of recent realizations

    Prospects for measurement and control of the scattering length of metastable helium using photoassociation techniques

    Full text link
    A numerical investigation of two-laser photoassociation (PA) spectroscopy on spin-polarized metastable helium (He*) atoms is presented within the context of experimental observation of the least-bound energy level in the scattering potential and subsequent determination of the s-wave scattering length. Starting out from the model developed by Bohn and Julienne [Phys. Rev. A \textbf{60}, (1999) 414], PA rate coefficients are obtained as a function of the parameters of the two lasers. The rate coefficients are used to simulate one- and two-laser PA spectra. The results demonstrate the feasibility of a spectroscopic determination of the binding energy of the least-bound level. The simulated spectra may be used as a guideline when designing such an experiment, whereas the model may also be employed for fitting experimentally obtained PA spectra. In addition, the prospects for substantial modification of the He* scattering length by means of optical Feshbach resonances are considered. Several experimental issues relating to the numerical investigation presented here are discussed.Comment: 9 pages, 7 figure

    Spectroscopic determination of magnetic-field-dependent interactions in an ultracold Yb(3P2)-Li mixture

    Get PDF
    We present experimental results on the inelastic and elastic interspecies interactions between ytterbium (Yb) in the metastable 3P2{}^3\mathrm{P}_2 state loaded into a deep optical lattice and spin polarized lithium (Li) in its ground state. Focusing on the mJ=0m_J = 0 magnetic sublevel of Yb(3P2{}^3\mathrm{P}_2), bias magnetic fields between 20 G and 800 G are investigated and significantly enhanced inelastic collision rates with high magnetic fields are found. In addition, by direct spectroscopy of the Yb Mott-insulator immersed in the Li Fermi gas an upper boundary of the background scattering length of the Yb(3P2,mJ=0{}^3\mathrm{P}_2, m_J=0)-Li(2S1/2,F=1/2,mF=+1/2{}^2\mathrm{S}_{1/2}, F=1/2, m_F=+1/2) system is estimated, revealing the absence of useful Feshbach resonances. These observations are qualitatively consistent with the theoretical calculations.Comment: 7 pages, 4 figure

    Standard Model tests with trapped radioactive atoms

    Full text link
    We review the use of laser cooling and trapping for Standard Model tests, focusing on trapping of radioactive isotopes. Experiments with neutral atoms trapped with modern laser cooling techniques are testing several basic predictions of electroweak unification. For nuclear β\beta decay, demonstrated trap techniques include neutrino momentum measurements from beta-recoil coincidences, along with methods to produce highly polarized samples. These techniques have set the best general constraints on non-Standard Model scalar interactions in the first generation of particles. They also have the promise to test whether parity symmetry is maximally violated, to search for tensor interactions, and to search for new sources of time reversal violation. There are also possibilites for exotic particle searches. Measurements of the strength of the weak neutral current can be assisted by precision atomic experiments using traps of small numbers of radioactive atoms, and sensitivity to possible time-reversal violating electric dipole moments can be improved.Comment: 45 pages, 17 figures, v3 includes clarifying referee comments, especially in beta decay section, and updated figure

    Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal

    Get PDF
    We measured by laser spectroscopy the isotope shifts between naturally-occurring even-isotopes of strontium ions for both the 5s\,\,^2S_{1/2}\to 5p\,\,^2P_{1/2} (violet) and the 4d\,\,^2D_{3/2}\to 5p\,\,^2P_{1/2} (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing 10310^3--10410^4 laser-cooled Sr+^+ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-level atom in interaction with two laser beams. This technique allowed us to increase the precision with respect to previously reported data obtained by optogalvanic spectroscopy or fast atomic-beam techniques. The results for the 5s\,\,^2S_{1/2}\to 5p\,\,^2P_{1/2} transition are ν88ν84=+378(4)\nu_{88}-\nu_{84}=+378(4) MHz and ν88ν86=+170(3)\nu_{88}-\nu_{86}=+170(3) MHz, in agreement with previously reported measurements. In the case of the previously unexplored 4d\,\,^2D_{3/2}\to 5p\,\,^2P_{1/2} transition we find ν88ν84=828(4)\nu_{88}-\nu_{84}=-828(4) MHz and ν88ν86=402(2)\nu_{88}-\nu_{86}=-402(2) MHz. These results provide more data for stringent tests of theoretical calculations of the isotope shifts of alkali-metal-like atoms. Moreover, they simplify the identification and the addressing of Sr+^+ isotopes for ion frequency standards or quantum-information-processing applications in the case of multi-isotope ion strings.Comment: 19 pages; 5 figures; accepted on Phys. Rev. A (http://pra.aps.org/
    corecore