Hannover 2010 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 10: Quantum Gases: Bosons II

Q 10.4: Talk

Monday, March 8, 2010, 17:15–17:30, E 001

Bose-Einstein condensates in micro-optical potentials — •Thomas Lauber, Johannes Küber, Oliver Wille, Martin Hasch, and Gerhard Birkl — Institut für Angewandte Physik, Technische Universität Darmstadt, Schlossgartenstraße 7, 64289 Darmstadt

The goal of our experiments is to study the coherence properties of Bose-Einstein condensates in micro-optical potentials. We use an 'all-optical' BEC of rubidium, which we prepare in a crossed dipole trap, generated by a 1070nm fiber laser. The atoms are loaded directly from a magneto-optical trap and are evaporatevly cooled to quantum degeneracy in the dipole trap by simply ramping down the laser power.

We create the optical micro-potentials by using microfabricated lenses illuminated with off-resonant laser light, either red- or blue-detuned. We implement various types of lenses, including microlens arrays, cylindrical lens arrays and a ring shaped lens. These lenses allow the creation of potentials that can be used as beam splitters, wave guides or mirrors for atoms on a sub-millimeter scale. The ring lens for example suggests the implentation of a one-dimensional geometry with periodic boundary conditions. As a tool to move the atoms along the waveguides, we use Bragg scattering to split or transfer the BEC in different momentum states.

We are going to report on the current status of our experiments.