Heidelberg 2015 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 18: Poster: Ultra-cold atoms, ions and BEC (with Q)
A 18.11: Poster
Dienstag, 24. März 2015, 17:00–19:00, C/Foyer
Bose-Einstein condensation in a hybrid trap for photoionization experiments — •Harry Krüger1, Bernhard Ruff2,3, Maik Schröder1, Jasper Krauser1, Philipp Wessels1,2, Juliette Simonet1, Markus Drescher2,3, and Klaus Sengstock1,2 — 1Zentrum für optische Quantentechnologien, Hamburg, Germany — 2Centre for Ultrafast Imaging, Hamburg, Germany — 3Institut für Experimentalphysik, Hamburg, Germany
Local photoionization of ultracold atoms shall offer insight into the coherence properties of a Bose-Einstein condensate (BEC). To access the corresponding quantum effects, we are setting up an experiment to observe correlations among electrons originating from a BEC ionized by a femtosecond laser pulse.
We present the design of our vacuum system consisting of a preparation and a science chamber with the atom transport provided by an optical tweezers approach. The transport is necessary because usual cooling techniques are difficult to implement in the science chamber where the particle detectors have to be shielded against stray fields. To realize quantum degeneracy in the preparation chamber, we perform forced evaporative cooling in a hybrid trap consisting of a magnetic quadrupole trap combined with a red-detuned optical dipole trap. We show experimental results for the evaporation efficiency and support these data by numerical simulations of the hybrid trap potential as well as the evaporation process itself.