Laser spectroscopy on Os_1hn- [Elektronische Ressource] : a prerequisite for the laser cooling of atomic anions / presented by Ulrich Warring

Dissertationsubmitted to theCombined Faculties for the Natural Sciences and forMathematicsof the Ruperto-Carola University of Heidelberg, Germanyfor the degree ofDoctor of Natural Sciencespresented byDipl.-Phys. Ulrich Warringborn in Wuppertal, GermanyDate of oral examination: 4 November 2009−Laser Spectroscopy on Os :A Prerequisite for the Laser Coolingof Atomic AnionsReferees:Priv.-Doz. Dr. Alban KellerbauerProf. Dr. Markus Oberthaler−Laser Spectroscopy on Os : A Prerequisite for the Laser Cool-ingofAtomicAnions–Laser cooling of neutral atoms or positive ions istoday routinely employed in numerous experiments. Negative ions, in contrast,have distinct characteristics which hamper the application of lasers for cooling.But in 1999, the discovery of the unique bound–bound electric dipole transition inthe negative osmium ion provided the motivation for a first cooling attempt. Thisthesis presents the first milestones toward the ultimate goal of laser cooling negativeosmium, including high-resolution laser spectroscopy of the relevant bound–bound4 6E1 transition. Its frequency – between the ground F and the D (bound)J9/2 e1192 −excited states – was determined to be 257.831190(35) THz in Os , in agreementwith a previous measurement, but two orders of magnitude more precise. Thedetermination of the resonant cross-section implicitly provided the corresponding−1Einstein A coefficient, which was found to be A≈ 330 s .