Controlling vibrational wave packets with intense, few-cycle laser pulses

Using three precisely timed laser pulses, we show experimentally that subvibrational period, nonresonant laser radiation can control a vibrational wave packet. One pulse launches the wave packet and the second modifies the potential energy surfaces as the wave packet moves and the third probes its time evolution by Coulomb explosion imaging. First, we observe D-2(+) wave packets up to the first half revival without a control pulse. Next, we apply the control pulse to split the wave packet when the wave packet is near the outer turning point. We observe that one piece remains in the bound state and the other propagates to the dissociation continuum. By varying the delay between the pump and control pulses, we control the branching ratios. By a quantum mechanical calculation, we also show that if carrier-envelope phases of subvibrational period pulses are controlled, it can break left-right symmetry during dissociation, freezing the electron on one of the two dissociating fragments during dissociation.