title: Measurement of Dipole Matrix Elements with a Single Trapped Ion.
abstract: We demonstrate a method to determine dipole matrix elements by comparing measurements of dispersive and absorptive light ion interactions. We measure the matrix element pertaining to the Ca II H line, i.e., the 4(2)S(1/2)↔4(2)P(1/2) transition of (40)Ca(+), for which we find the value 2.8928(43) ea(0). Moreover, the method allows us to deduce the lifetime of the 4(2)P(1/2) state to be 6.904(26) ns, which is in agreement with predictions from recent theoretical calculations and resolves a long-standing discrepancy between calculated values and experimental results.
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hettrich
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Ruster
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Kaufmann
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020 Innsbruck, Austria.|Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
authors.forename: C F
authors.initials: CF
authors.lastname: Roos
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: C T
authors.initials: CT
authors.lastname: Schmiegelow
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Schmidt-Kaler
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: U G
authors.initials: UG
authors.lastname: Poschinger