The role of optical and electron-wavepacket interferences in optimal control experiments
Ultrafast and ultraintense laser pulses are a common tool for optimally controlling chemical and molecular dynamics, due primarily to the simplicity of temporally shaping these pulses. Unfortunately, the optimal control pulses found in these experiments do not "explain themselves"--that is, it is generally unknown how these pulses optimally guide a system to its target state. We have found that a twin-peaked pulse (TPP), with a well-defined relative phase between the two peaks, can optimally control Coulomb explosion branching ratios in CO2. In an effort to "unpack" this pulse, I will focus in this talk on one aspect of this control--the effect of TPP relative phase on ionization yields. We have found in our experiments a 2π-periodic variation in Xe+ yield as a function of TPP relative phase. Two different mechanisms that can lead to such a modulation have been considered: optical interference of the two peaks and wavepacket interference of the ionized electrons. Our experimental results will be compared to models describing both effects to discover which process is dominant in optimal control experiments.
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