Berlin 2005 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 38: Fallen & Kühlung I

Q 38.1: Vortrag

Dienstag, 8. März 2005, 11:15–11:30, HU 2002

Double-EIT ground-state laser cooling without blue-sideband heating — •Jörg Evers and Christoph H. Keitel — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg

Electromagnetically induced transparency (EIT-) cooling is a promising technique for cooling trapped atoms or ions to the motional ground state, which relies on atomic coherence and interference effects [1]. In this talk, we discuss a laser cooling scheme based on double-EIT, making use of a four-level setup in tripod configuration [2]. The additional fourth atomic state is coupled by a strong coupling laser field to the upper state of the usual three-level setup of single-EIT cooling. This effectively allows to create two EIT structures in the absorption spectrum of the system to be cooled, which may be controlled by the coupling laser field parameters to cancel both the carrier- and the blue-sideband excitations. In leading order of the Lamb-Dicke expansion, this suppresses all heating processes. As a consequence, the double-EIT scheme can be used to lower the cooling limit by a factor of order of the Lamb-Dicke parameter squared as compared to single-EIT cooling. We also extend the study to multiple-EIT schemes with more than two EIT structures, which for example allows to cool at two different trap frequencies simultaneously. 0.5cm

[1] G. Morigi, J. Eschner and C. H. Keitel, Phys. Rev. Lett. 85, 4458 (2000); C. F. Roos, D. Leibfried, A. Mundt, F. Schmidt-Kaler, J. Eschner, and R. Blatt, Phys. Rev. Lett. 85, 5547 (2000).

[2] J. Evers and C. H. Keitel, Europhys. Lett. 68, 370 (2004).