Logo PTB

Calcium Bose-Einstein-Condensate

Since nearly fifteen years Bose-Einstein Condensates (BECs) are prominent tools to investigate fundamental properties of matter and matter-light interaction. Up to now, most research focused on alkaline BECs. However, for precision experiments alkaline earth atoms offer a distinct advantage: The narrow optical transitions of their intercombination lines promise to be a sensitive probe for various novel types of measurements.

We have, for the first time, produced a BEC of alkaline earth atoms: After a two stage MOT cooling we load 4 .106 40Ca atoms at a temperature of 20 µK into a crossed dipole trap. By evaporative cooling we reach quantum degeneracy within 1.5 s with 105 atoms.

Absorption image of the density distribution of an atomic ensemble consisting of a thermal cloud with a BEC in the center. The radial and axial trap frequencies at this stage are typically 400Hz and 50 Hz, respectively. The number of atoms in the BEC is 2·104 .

The BEC-Team (from left to right): Oliver Appel, Sebastian Kraft, Fritz Riehle, Felix Vogt and Uwe Sterr at the occasion of Felix’ PhD defense.


Dr. Uwe Sterr Phone: +49-531 592-4310
Fax: +49-531 592-69 4310
E-mail: Uwe Sterr