We have performed continuous slowing of an atomic beam to load a magneto-optical trap (MOT) on axis. To avoid the undesirable effects of the strong slowing laser on the performance of the MOT, a dark spot in the center of the slowing laser beam is used. We varied the spot size and the slowing-laser frequency and intensity to optimize the number of trapped atoms. Our “dark-spot” slowing increased the number of trapped atoms by a factor of 30, allowing us to trap $\sim {10}^9$ atoms in the MOT.

• Received 14 November 1997

DOI:https://doi.org/10.1103/PhysRevA.59.882