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A: Fachverband Atomphysik

A 3: Ultracold Atoms: Manipulation and Detection (with Q)

A 3.5: Vortrag

Montag, 14. März 2011, 11:30–11:45, SCH 251

Feedback Cooling of a Single Neutral Atom — •Christian Sames, Markus Koch, Maximilian Balbach, Haytham Chibani, Alexander Kubanek, Alexei Ourjoumtsev, Pepijn Pinkse, Karim Murr, Tatjana Wilk, and Gerhard Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching, Germany

Feedback is a powerful tool to control the evolution of classical systems. Fast electronics enables its extension towards the quantum domain, namely the control of the motion of a single neutral atom inside a high-finesse optical resonator. The atom is trapped in an optical dipole trap and interacts strongly with a single mode of the resonator. The interaction strength determines the resonance condition of the coupled system, depending on the atomic position, and hence governs the intensity of a transmitted probe beam. We analyze the flux of the transmitted photons which carries information about the atomic position and velocity, and alter the dipole force in such a way that it counteracts the atomic motion [1]. With this feedback technique we enhance the storage time of the atom in the resonator by at least 2 orders of magnitude, reaching values of more than 17 seconds with an average of more than 1 second. Additionally, we demonstrate cooling of the single atom by this technique to a temperature of about 160 µK [2]. Feedback cooling of a single atom hence rivals state-of-the-art laser cooling with the advantage that much less optical access is required.

[1] A. Kubanek et al., Nature 462, 898 (2009).

[2] M. Koch et al., Phys. Rev. Lett. 105, 173003 (2010).