Trapping of Bose-Einstein condensates in a three-dimensional dark focus generated by conical refraction
Dominik Pfeiffer, Ludwig Lind, J. Küber +5 more
We present an efficient three-dimensional dark-focus optical trapping potential for neutral atoms and Bose-Einstein condensates. This ``optical bottle'' is created by a single blue-detuned light field exploiting the phenomenon of conical refraction occurring in biaxial crystals. The conversion of a Gaussian input beam to the bottle beam has an efficiency of close to 100% and the optical setup requires the addition of the biaxial crystal and a circular polarizer only. Based on the conical-refraction theory, we derive the general form of the potential, the trapping frequencies, and the potential barrier heights. We present experiments on confining a $^{87}\mathrm{Rb}$ Bose-Einstein condensate in three dimensions. We determine the trap shape, the vibrational frequencies along the weak axis, as well as the lifetime of ultracold atoms in this type of potential.
arXiv:1705.02425•Physical Review A•Nov 27, 2023•9 citations