Accumulative effects in temporal coherent control

This paper analyzes the result of a temporal coherent control experiment using trains of ultrashort laser pulses in the situation where the laser repetition period is smaller than the relaxation times of the system. We focus on the accumulative effects present in sequential two-photon absorption. It is shown that stimulated emission due to the accumulation of population in the excited state give an important contribution to the coherently controlled process. Excellent agreement is obtained in the comparison between experiments in rubidium vapor and theory, where resonant pulse propagation is also taken into account.