Quantum Control of Wave Packet Evolution with Tailored Femtosecond Pulses

Using theory to guide the choice of pulse shape, we have synthesized frequency-chirped laser pulses and used them to control the evolution of vibrational wave packets on the $B$ excited state of iodine. A negatively chirped pulse produces a wave packet at the target time localized about an internuclear position and momentum of our choice. An approximately time-reversed pulse, however, produces a delocalized wave packet. The experimental results are in very good qualitative agreement with quantum simulations.