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A: Fachverband Atomphysik
A 30: Precision Spectroscopy of Atoms and Ions V
A 30.4: Talk
Thursday, March 5, 2009, 17:30–17:45, VMP 6 HS-B
Precision measurement of decay branching ratios in a single trapped Ca+ ion — •Rene Gerritsma1, Gerhard Kirchmair1,2, Florian Zähringer1,2, Jan Benhelm1,2, Rainer Blatt1,2, and Christian Roos1,2 — 1Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Otto-Hittmair-Platz 1, A-6020 Innsbruck, Austria — 2Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
We report on precision measurements of the 4P3/2 decay branching ratios in Ca+ [R. Gerritsma et al., Eur. Phys. J. D 50, 13 (2008)]. Absorption and emission lines in Ca+ have been used in many astrophysical observations, such as of galaxies, interstellar clouds and dust disks surrounding stars. Here, an accurate knowledge of transition frequencies and oscillator strengths is desired. On the theoretical side considerable effort is devoted to precise structure calculations of singly charged alkali earth ions such as Ca+. For comparison to theory precise measurements of branching ratios and lifetimes are needed. Measurements of these quantities in literature are often based on experiments in ion beams or trapped clouds of ions. In our approach, the use of a single trapped ion eliminates errors due to depolarizing collisions while allowing high fidelity state preparation and detection. Furthermore, we improve the precision by a new technique based on repetitive pumping to the 4P3/2 state. In this way we determine the branching fractions with sub-precent precision and a forty-fold improvement with respect to the previously best known values.