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PACS numbers: 32.80.Rm, 42.65.Ky, 42.65.Re, 42.79.Nv
Abstract:
At the core of attosecond science lies the ability to generate laser pulses of subfemtosecond duration. In
tabletop devices the process relies on high-harmonic generation, where a major challenge is to obtain high
yields and high cutoff energies required for the generation of attosecond pulses. We develop a computational
method that can simultaneously resolve these issues by optimizing the driving pulses using quantum optimal
control theory. Our target functional, an integral over the harmonic yield over a desired energy range, leads
to a remarkable cutoff extension and yield enhancement for a one-dimensional model H atom. The physical
enhancement process is shown to be twofold: the cutoff extension is of classical origin, whereas the yield
enhancement arises from increased tunneling probability. The scheme is directly applicable to more realistic
models and, within straightforward refinements, also to experimental verification.
