Stuttgart 2012 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 14: Quantengase: Bosonen 2
Q 14.1: Talk
Monday, March 12, 2012, 16:30–16:45, V47.02
Bose-Einstein condensates in an optical storage ring — •Thomas Lauber1, Johannes Küber1, Felix Schmaltz1, Jordi Mompart2, and Gerhard Birkl1 — 1Institut für Angewandte Physik, Technische Universität Darmstadt, Schlossgartenstraße 7, 64289 Darmstadt — 2Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain
We present the experimental investigation of Bose-Einstein condensates (BEC) in a novel optical storage ring.
The storage ring is based on the application of conical refraction as a new technique for creation of toroidal potentials. An appropriately polished birefringent crystal is used to diffract light to a ring structure of selectable diameter consisting of two concentric bright rings with a dark ring in between. Depending on the detuning with respect to the atomic resonance, conical refraction gives rise to either creating two rings with attractive potential or a potential that gives radial confinement between two repulsive rings. In both cases we use a light sheet for confinement in the dimension perpendicular to the ring plane.
Conical refraction allows numerous possibilities for experimental investigations of a BEC in a potential with periodic boundary conditions. We present results for a BEC that is loaded into a ring with a diameter of 340 µm and accelerated by means of a Bragg-pulse. We achieve BECs with a mean momentum of 2 or 4 ℏk and can observe multiple turns in the ring. Conical refracted light is a new approach towards integrated atom-optics and can be easily combined with dipole potentials from micro-optical elements to create more sophisticated configurations.