  In this paper, we present a technique for magneto-optical cooling and
trapping of neutral atoms using a single laser. The alternating-frequency
magneto-optical trap (AF-MOT) uses an agile light source that sequentially
switches between cooling and repumping transition frequencies by tuning the
injection current of the laser diode. We report on the experimental
demonstration of such a system for 87Rb and 85Rb based on a micro-integrated
extended cavity diode laser (ECDL) performing laser frequency jumps of up to
6.6 GHz with a tuning time in the microsecond regime and a repetition rate of
up to 7.6 kHz. For that, a combination of a feed-forward for coarse frequency
control and a feedback for precise locking was used. We discuss the results of
the AF-MOT characterization in terms of atom numbers and cloud temperature for
different operation parameters.
