Optimal control for manipulating vibrational wave packets through polarizability interactions induced by nonresonant laser pulses

On the basis of optimal control theory, we numerically study how to optimally manipulate molecular vibrational dynamics by using cycle -averaged polarizability interactions induced by mildly intense nonresonant laser (NR) pulses. As the essential elements to be controlled are the probability amplitudes, namely, the populations and the relative phases of the vibrational eigenstates, we consider three fundamental control objectives: selective population transfer, wave -packet shaping that requires both population control and relative -phase control, and wave -packet deformation suppression that solely requires relative -phase control while avoiding population redistribution. The nontrivial control of wave -packet deformation suppression is an extension of our previous study on wave -packet spreading suppression. Focusing on the vibrational dynamics in the B state of I2 as a case study, we adopt optimal control simulations and model analyses under the impulsive excitation approximation to systematically examine how to achieve the control objectives with shaped NR pulses. Optimal solutions are always given by NR pulse trains, in which each pulse interval and each pulse intensity are adjusted to cooperate with the vibrational dynamics to effectively utilize the quantum interferences to realize the control objectives with high probability.