Coherent Control of Molecular Orientation by a Terahertz Few-Cycle Laser Pulse

The coherent control of molecular orientation by a terahertz few-cycle laser pulse is theoretically studied.It is demonstrated that the Geld-free molecular orientation results from the interference contributions between the odd and even rotational wave packet,and therefore the constructive and destructive interferences lead to the observation of the positive and negative orientations,corresponding to the positive and negative degrees.Furthermore,the enhancement or suppression of the molecular orientation can be coherently manipulated by precisely controlling the carrier-envelope phase of the terahertz few-cycle pulse.