Field-free molecular orientation control by two ultrashort dual-color laser pulses

We show that molecular orientation can be controlled by sequential three-photon Raman excitations with time-delayed dual-color ultrashort laser pulses. The field-free molecular orientation created by a dual-color ultrashort laser pulse can be significantly enhanced or completely suppressed when another in-phase or antiphase dual-color ultrashort laser pulse is applied at its full revival time. By applying the second dual-color ultrashort laser pulse at the half-revival time, the odd and even rotational wave packets for the impulsive molecular orientation can be promoted and depressed by changing its carrier-envelope phase.