Active control of the molecular rotational wave packet using two laser pulses

The rotational wave packet of linear molecules excited non-adiabatically by a femtosecond laser pulse is controlled actively using the second laser pulse. We propose a novel strategy to determine the optimal delay times of the two laser pulses to modify the coherence of the molecular rotational wave packet, by which the molecular alignment generated by the first pulse is suppressed or enhanced by selecting the respective delay times. This control scheme can be applied to molecular alignment using a multi-pulse laser field.