Hamburg 2009 – scientific programme
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A: Fachverband Atomphysik
A 37: Precision Spectroscopy of Atoms and Ions VII
A 37.5: Talk
Friday, March 6, 2009, 15:30–15:45, VMP 6 HS-B
Mg frequency measurement via telecom fibre network — •Andre Pape1, Jan Friebe1, Matthias Riedmann1, Temmo Wübbena1, Ernst M. Rasel1, Wolfgang Ertmer1, Osama Terra2, Gesine Grosche2, Katharina Predehl2,3, Thorsten Feldmann2, Burghard Lipphardt2, and Harald Schnatz2 — 1Institut für Quantenoptik, Universität Hannover, Welfengarten 1, 30167 Hannover — 2Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig — 3Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching
The alkaline earth magnesium (Mg) is an interesting candidate for a future optical clock based on ensembles of neutral atoms. We report on a recently performed characterization of the Mg frequency standard at the Institute of Quantum Optics (IQ) in Hanover via a telecom fibre network connecting IQ with the optical frequency standards at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig. The stability of PTB’s Ca clock laser is transferred via an actively stabilized 73 km long telecom fibre for direct optical comparison to the Mg frequency standard by means of a telecom fibre laser and two fs frequency combs. The investigated clock transition 1S0 → 3P1 in cold free falling Mg atoms is probed in a Ramsey-Bordé interferometer with subsequent detection of the excited atoms in a MOT in the triplet system. To enable long term stability and accuracy a passive hydrogen maser at IQ is used and compared to a Cs fountain clock at PTB. We present the results of the measurement of the Mg clock lasers’ short term stability and the characterization of the Mg frequency standard.