Hamburg 2009 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 15: Poster I

A 15.50: Poster

Dienstag, 3. März 2009, 16:30–19:00, VMP 9 Poster

Bose Einstein Condensates on the surface of a glass prism — •Helmar Bender, Phillipe Courteille, Claus Zimmermann, and Sebastian Slama — Physikalisches Institut, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 14, D-72070 Tübingen

The main focus of our experiments ist the interaction of ultra cold atoms with a dielectric surface. In our case the surface is the facet of a glass prism. An evanescent wave created by total reflection of a laser beam at this facet allows us to generate a dipole potential acting on atoms close to the surface. This potential makes it possible to compensate for the attractive Casimir-Polder (CP) force which is playing a dominant role at very small distances from the surface. The sum of the two potentials is able to form a controllable barrier at a distance of only a few hundred nanometers from the surface. By using a magnetic trap we are able to shift a Bose Einstein Condensate (BEC) in a controlled way to this barrier. The atoms overlapping with the evanescent wave of a far detuned laser beam shift the phase of the totally reflected light proportionally to the number of atoms. Monitoring this phase shift as a function of time provides information on number fluctuations in a BEC. Another interesting perspective of our setup is the reflection of matterwaves from the barrier for the measurement of CP-forces. In the long term we plan to deposit nano structured metal layers on the surface. Excitation of surface plasmon polaritons in these layers enhances the evanescent wave intensity and thus the dipole potential locally. We will investigate such systems for tailoring of nanometric surface traps with the perspective of a photonic atom chip.