We report the experimental observation of a lensing effect on a Bose-Einstein condensate expanding in a moving 1D optical lattice. The effect of the periodic potential can be described by an effective mass dependent on the condensate quasi-momentum. By changing the velocity of the atoms in the frame of the optical lattice we induce a focusing of the condensate along the lattice direction. The experimental results are compared with the numerical predictions of an effective 1D theoretical model. Besides, a precise band spectroscopy of the system is carried out by looking at the real-space propagation of the atomic wavepacket in the optical lattice.
@article{arxiv.cond-mat/0303626,
title = {Optically-induced lensing effect on a Bose-Einstein condensate expanding in a moving lattice},
author = {L. Fallani and F. S. Cataliotti and J. Catani and C. Fort and M. Modugno and M. Zawada and M. Inguscio},
journal= {arXiv preprint arXiv:cond-mat/0303626},
year = {2009}
}
Comments
5 pages, 4 figures; minor changes applied and typos corrected; a new paragraph added; some references updated; journal reference added