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Q: Quantenoptik und Photonik

Q 53: Fallen und Kühlung II

Q 53.5: Talk

Wednesday, March 15, 2006, 15:30–15:45, HII

Vacuum-Stimulated Cooling of Single Atoms in Three Dimensions — •Markus Hijlkema, Stefan Nußmann, Karim Murr, Bernhard Weber, Simon Webster, Holger Specht, Axel Kuhn, and Gerhard Rempe — Max Planck Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching

Control of light-matter interactions at the single-atom and single-photon level can be achieved in the strong coupling regime of cavity quantum electrodynamics, where atom and cavity form a single entity. With our experimental setup we are able to capture, cool and hold a single atom at rest inside a microcavity, ensuring a strong and constant atom-cavity coupling on a timescale of several seconds. To provide a trapping potential, we use a far off-resonant standing wave dipole trap perpendicular to the cavity axis, where each antinode of the standing wave provides three dimensional confinement.[1] We have now discovered that the orthogonal arrangement of the trapping laser, the cavity vacuum and an additional cooling laser gives rise to a unique combination of friction forces acting on the atom along all three directions. This novel three dimensional cooling scheme allows us to easily catch and cool a single atom into the dipole trap inside the high-finesse cavity. We show that a simple theoretical model based on a two-level atom can explain the origin of these forces.[2] Inside the trap,very low temperatures are reached, leading to average single-atom trapping times exceeding 15 seconds, unprecedented for a strongly coupled atom under permanent observation. [1] Nußmann et al. Phys. Rev. Lett. 95 173602 (2005) [2] Nußmann et al, Nature Physics 1 , 120 (2005)