Hamburg 2009 – scientific programme
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A: Fachverband Atomphysik
A 30: Precision Spectroscopy of Atoms and Ions V
A 30.2: Talk
Thursday, March 5, 2009, 17:00–17:15, VMP 6 HS-B
Direct Frequency Comb Spectroscopy of Metal Ions using Quantum Logic — •Boerge Hemmerling1, Daniel Nigg1, Lukas An der Lan2, Birgit Brandstätter2, and Piet O. Schmidt1 — 1QUEST Institute for Quantum Metrology, Physikalisch-Technische Bundesanstalt, Leibniz Universität Hannover, Braunschweig, Germany — 2Institut für Experimentalphysik, Universität Innsbruck, Austria
Improving the interpretation of quasar absorption spectra for the search of a possible temporal variation of the fine-structure constant on cosmological time scales requires more precise frequency measurements of certain transitions in metal ions such as Ca+, Ti+ and Fe+ [1].
We are developing a versatile setup for precision spectroscopy of these ions with a complex level structure. The ions are sympathetically cooled by 25Mg+ in a linear Paul trap. A femto-second optical frequency comb will be used as a tunable spectroscopy probe, ideally covering the whole spectrum of interest. Quantum logic techniques will be employed for efficient state preparation, ground state cooling and detection of the spectroscopy signal. We will present the latest results of our experiments and a detailed theoretical analysis of the interrogation scheme for Ca+. We expect that direct frequency comb spectroscopy produces a maximum fluorescence rate of (∼ 100 photons/s), which will be detected by measuring the increase of the vibrational quantum number of the ion crystal due to photon scattering.
[1] J. C. Berengut, V. A. Dzuba, V. V. Flambaum, M. V. Marchenko and J. K. Webb, arXiv:physics/0408017 (2006)