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Very sharp, low-energy structures observed in photoelectron spectra reveal the population of autoionizing states in krypton and argon in strong laser fields over a large range of different wavelengths. The energies of the electrons, emitted by autoionization in a field-free environment, provide direct information about the spectrum of states involved. Despite their ability to resist ionization by the populating laser pulse, we demonstrate the possibility to promote the excited electrons into the continuum by subsequent absorption of a single photon. Thus, applying a classical pump-probe scheme, we are able to manipulate the autoionization contribution on a picosecond time scale. Different scenarios for the creation of autoionizing states in strong laser fields are discussed.

We present a comparative study of nonsequential double ionization (NSDI) of N${}_{2}$ and Ar exposed to near-single-cycle laser pulses. The NSDI process is investigated using carrier-envelope-phase-tagged electron-ion coincidence spectroscopy. The measured NSDI spectra of N${}_{2}$ and Ar exhibit a striking resemblance. In particular, the correlated two-electron momentum distribution arising from NSDI of N${}_{2}$ also displays a cross-shape very similar to that reported for Ar [Bergues et al., Nat. Commun. 3, 813 (2012)]. We interpret our results in terms of recollision-excitation with subcycle depletion and discuss how this mechanism accounts for the observed similarities and differences in the ionization behavior of the two species.