Abstract
The use of quantum interference to examine the transient behavior of photon switching in cold 87 Rb atoms was discussed. It was observed that the cold traps were produced by a vapor-cell magneto-optical trap (MOT). It was found that single photon switching was achieved under the condition that the pulse length of the switching field was set equal to the delay time of the probe propagation in a medium. The results shows that single-photon switching in the four-state system was feasible with respect to the rise time of the probe absorption.