Coherent control and entanglement in the attosecond electron-recollision dissociation ofD2+

Abstract

We examine the attosecond electron recollision dissociation of D{sub 2}{sup +} recently demonstrated experimentally [H. Niikura et al., Nature (London) 421, 826 (2003)] from a coherent control perspective. In this process, a strong laser field incident on D{sub 2} ionizes an electron, accelerates the electron in the laser field to eV energies, and then drives the electron to recollide with the parent ion, causing D{sub 2}{sup +} dissociation. A number of results are demonstrated. First, a full dimensional strong field approximation model is constructed and shown to be in agreement with the original experiment. This is then used to rigorously demonstrate that the experiment is an example of coherent pump-dump control. Second, extensions to bichromatic coherent control are proposed by considering dissociative recollision of molecules prepared in a coherent superposition of vibrational states. Third, by comparing the results to similar scenarios involving field-free attosecond scattering of independently prepared D{sub 2}{sup +} and electron wave packets, recollision dissociation is shown to provide an example of wave-packet coherent control of reactive scattering. Fourth, this analysis makes clear that it is the temporal correlations between the continuum electron and D{sub 2}{sup +} wave packet, and not entanglement, that are crucial for the subfemtosecondmore » probing resolution demonstrated in the experiment. This result clarifies some misconceptions regarding the importance of entanglement in the recollision probing of D{sub 2}{sup +}. Finally, signatures of entanglement between the recollision electron and the atomic fragments, detectable via coincidence measurements, are identified.« less