One important factor which determines efficiency of loading cold atoms into an optical dipole trap from a magneto-optical trap is the distance between the trap centers. By studying this efficiency for various optical trap depths (2–110  mK) we find that for optimum dipole trap loading, longitudinal displacements up to 15  mm are necessary. An explanation for this observation is presented and compared with other work and a simple analytical formula is derived for the optimum distance between the trap centers.

http://link.aps.org/abstract/PRA/v79/e013408