Stuttgart 2012 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 34: Poster 1

Q 34.8: Poster

Tuesday, March 13, 2012, 16:30–19:00, Poster.I+II

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

We present an optimized loading and evaporation strategy for the all-optical generation of Bose-Einstein condensates (BECs) of rubidium in a crossed dipole trap with a multi-frequency laser at 1070nm. We characterize highly power-dependent two-body losses resulting from optical pumping to higher-energy hyperfine states and show an efficient path to evaporative cooling to reach a BEC of 25000 Rb atoms [1].

Our experiment demonstrates the combination of various attractive and repulsive trapping potentials to shape a toroidal waveguide. We use conical refraction produced by a transparent biaxial crystal to create two ring-shaped repulsive optical potentials with a dark ring in between. We combine them with an attractive light sheet to create a toroidal trap.

In our experiments we use the toroidal potential to trap atoms loaded from the crossed dipole trap and guide them along the ring structure. Using a one-dimensional optical lattice we accelerate the condensed atoms and observe cycling of the atoms in the trapping potential.

[1] T. Lauber et al., Phys. Rev. A 84, 043641, (2011).