Abstract

We have performed laser cooling experiments in a standard magneto-optical trap on a sample of Rubidium-87 atoms. Extended cavity diode lasers were used to cool and trap the atoms and probe the resulting ultracold sample. Coherent transient effects were investigated in the transmitted intensity of a frequency-modulated probe laser beam through a sample of trapped atoms. The transient oscillations were observed when the frequency of the probe laser beam crossed a resonance of the atoms in a time that is on the order of the lifetime of the excited state. A theoretical model describing the transients has been developed further to take into account the characteristic frequency- and amplitude-modulation behaviour of current-modulated laser diodes. In addition, effects due to the probe laser linewidth and finite absorption length of the sample are included.

© 1998 IEEE