Osnabrück 2002 – scientific programme

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Q: Quantenoptik

Q 511: Fallen und Kühlung II

Q 511.5: Talk

Friday, March 8, 2002, 15:00–15:15, HS 22/B01

Sympathetic Cooling with Two Atomic Species in an Optical Trap — •Marcel Mudrich¹, Stephan Kraft¹, Jörg Lange¹, Kilian Singer¹, Rudi Grimm², Allard Mosk¹, and Matthias Weidemüller¹ — ¹Max-Planck-Institut für Kernphysik, Heidelberg — ²Institut für Experimentalphysik, Universität Innsbruck

We simultaneously trap ultracold lithium and cesium atoms in an optical dipole trap formed by the focus of a CO₂ laser and study the exchange of thermal energy between the gases [1,2]. The cesium gas, which is optically cooled to 20 µK, efficiently decreases the temperature of the lithium gas through sympathetic cooling. The measured cross section for thermalizing ¹³³Cs-⁷Li collisions is 8 × 10⁻¹² cm², for both species in their lowest hyperfine ground state. Besides thermalization, we observe evaporation of lithium purely through elastic cesium-lithium collisions (sympathetic evaporation).

[1] A. Mosk et al., Appl. Phys. B, in press.

[2] M. Mudrich et al., arXiv:physics/0111213.