Controlling coherent population transfer in molecular alignment using two laser pulses

In the two-pulse laser field alignment, the enhancement or suppression of molecular alignment can be achieved after the second pulse. We demonstrate that depending on the temporal separation between two aligning pulses, the population can be transferred either further to the rotational levels ( Δ J = ± 2 ) populated by the first pulse or back to the initial state, leading to the enhancement or suppression of molecular alignment. We clarify that the coherent population transfer is maximized and/or minimized as the delay time of the two pulses equals to a full revival and/or a half revival.