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arXiv · 1309.0786

Optimal control of strong-field ionization with time-dependent density-functional theory

M. Hellgren·E. Rasanen·E. K. U. Gross
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Abstract

We show that quantum optimal control theory (OCT) and time-dependent density-functional theory (TDDFT) can be combined to provide realistic femtosecond laser pulses for an enhanced ionization yield in many-electron systems. Using the H$_2$-molecule as a test case, the optimized laser pulse from the numerically exact scheme is compared to pulses obtained from OCT+TDDFT within the TD exact-exchange (TDEXX) and the TD local-density approximation (TDLDA). We find that the TDDFT-pulses produces an ionization yield of up to 50% when applied to the exact system. In comparison, pulses with a single frequency but the same fluence typically reach to yields around 5-15%, unless the frequency is carefully tuned into a Fano-type resonance that leads to $\sim 30%$ yield. On the other hand, optimization within the exact system alone leads to yields higher than 80%, demonstrating that correlation effects beyond the TDEXX and TDLDA can give rise to even more efficient ionization mechanisms.

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M. Hellgren, E. Rasanen, E. K. U. Gross. 2013-09-03. Optimal control of strong-field ionization with time-dependent density-functional theory. https://doi.org/10.1103/physreva.88.013414

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