Controlling field free molecular orientation with microwave pulses

We demonstrate a scheme to achieve the optimized control of field free molecular orientation. We show that operating with resonant microwave pulses, the phases of the major components of the oriented wave packet can propagate in such a way that the cosines of their differences approach their maxima/minima simultaneously. Thus the orientation degree can be completely controlled by purposively populating the oriented wave packet. And meanwhile, the orientation duration is optimized. This scheme can also be used to produce the cyclic state starting from which sustainable orientation can be obtained.