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Q: Quantenoptik und Photonik

Q 38: Poster Fallen und Kühlung

Q 38.12: Poster

Donnerstag, 25. März 2004, 14:00–16:00, Schellingstr. 3

Optical Trapping and Cooling of Fermionic and Bosonic Magnesium — •Albane Douillet, Tanja E. Mehlstäubler, Nils Rehbein, Ernst M. Rasel, and Wolfgang Ertmer — Institut für Quantenoptik, Universität Hannover, Welfengarten 1, 30167 Hannover.

We report on the status of our new experimental apparatus for precision spectroscopy of ultra cold fermionic and bosonic magnesium atoms. Both isotopes are captured from a slowed thermal magnesium beam and pre-cooled in a magneto-optical trap (MOT). Up to 10⁸ atoms can be trapped with 60 mW light tuned to the transition 3¹S₀→ 3¹P₁ at 285 nm. Time-of-flight measurements indicate atomic temperatures of about 3 mK, slightly above the Doppler limit (1.9 mK). The experiment will explore promising avenues towards the µKelvin regime with magnesium, such as quench cooling, which was recently very successfully applied for calcium. The need for effective cooling methods was demonstrated by recent measurements with our Ramsey-Borde interferometer. The residual atomic motion was one of the major limitations for the achieved resolutions of about 290 Hz. For the interferometer we are developing a frequency-doubled Nd:YVO₄-disc laser, which provides about 1 W at 914 nm (TEM₀₀).