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Q: Quantenoptik und Photonik

Q 32: Quantengase I

Q 32.8: Vortrag

Dienstag, 8. März 2005, 12:30–12:45, HU Kinosaal

Optical Feshbach resonances — •Klaus Winkler¹, Matthias Theis¹, Gregor Thalhammer¹, Rudolf Grimm^1,2, and Johannes Hecker Denschlag¹ — ¹Institut für Experimentalphysik, Universität Innsbruck, Austria — ²Institut für Quantenoptik und Quanteninformation, Innsbruck, Austria

We demonstrated optical tuning of the scattering length in a Bose-Einstein condensate as predicted by Fedichev et al. [1]. In our experiment atoms in a ⁸⁷Rubidium condensate were exposed to laser light tuned close to the transition frequency to a molecular state. The optical coupling of the atomic scattering state to the molecular state gives rise to what is called an optical Feshbach resonance. We showed that the optical Feshbach resonance can be induced via one or two photon transitions. While for the one photon transition we coupled to an excited molecular state [2], we used a stimulated Raman scheme for the two photon case to couple to the molecular ground state [3]. By controlling the power and the detuning of the lasers we were able to change the atomic scattering length over a wide range. We identified Bragg spectroscopy as a fast method (<100µs) to measure the scattering length of the atoms in view of rapid laser-driven atomic losses.

[1] P.Fedichev et al., Phys.Rev.Lett. 77, 2913 (1996)

[2] M. Theis et al., Phys.Rev.Lett. 93, 123001 (2004)

[3] G. Thalhammer et al., cond-mat 0409552 (2004)