Double-EIT ground-state laser cooling without blue-sideband heatingJ. Evers1 and C. H. Keitel2, 1
1 Theoretische Quantendynamik, Fakultät für Physik und Mathematik Universität Freiburg - Hermann-Herder-Straße 3, 79104 Freiburg, Germany
2 Max-Planck-Institut für Kernphysik - Saupfercheckweg 1, 69117 Heidelberg, Germany
received 24 June 2004; accepted 2 September 2004
published online 1 October 2004
We discuss a laser cooling scheme for trapped atoms or ions which is based on double electromagnetically induced transparency (EIT) and makes use of a four-level atom in tripod configuration. 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.
32.80.Pj - Optical cooling of atoms; trapping.
42.50.Gy - Effects of atomic coherence on propagation, absorption, and amplification of light; electromagnetically induced transparency and absorption.
42.50.Vk - Mechanical effects of light on atoms, molecules, electrons, and ions.
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