Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 50: Poster Ultrakalte Atome
Q 50.13: Poster
Thursday, March 13, 2008, 16:30–19:00, Poster C2
Continuous loading of calcium atoms into an optical dipole trap — •Purbasha Halder, Chih-Yun Yang, Oliver Appel, Dirk Hansen, and Andreas Hemmerich — Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg
Alkaline-earth metals are interesting candidates for novel laser cooling schemes due to the presence of narrow intercombination lines in addition to strong principal fluorescence lines. We demonstrate an efficient scheme for continuously loading Ca atoms into a ground-state (1S0) optical dipole trap (ODT) at 532nm. The ODT is loaded from a MOT in the triplet metastable state (3P2), by spatially selective optical pumping. This is done by careful superposition of the dipole trap laser on a depumping laser at 430 nm.
With this setup we achieve a cold ensemble of 105 atoms at 40 µ K and a phase space density of 4·(10−5). The loading and subsequent evaporation and cross-dimensional relaxation stages are well described by a simple model. We also point out that a comparable scheme could be employed to load a dipole trap with 3P0 atoms.
We are now setting up a new dipole laser at 1064 nm. We will be trying out a crossed dipole trap with which we hope to achieve efficient evaporative cooling and eventually reach quantum degeneracy. Here, we present the latest developments and the current status of our experiment.