Controlling the strong field dynamics by a time-delayed near- and mid-infrared two-color laser field

We theoretically demonstrate that the strong field dynamics such as above-threshold ionization and high-order harmonic generation can be significantly altered by the introduction of the time-delayed two-color laser field consisting of the near-infrared and mid-infrared frequencies. Specifically we apply the idea to the one-dimensional hydrogen atom, and show that the strong field dynamics significantly depend on the time delay between the two fields, as represented, for instance, by the change of the cutoff energies of above-threshold ionization and high-order harmonic generation. It turns out, however, that the delay dependence is different for those processes. In particular, if the duration of the near-infrared pulse is as short as a few cycles, its carrier-envelope phase also plays a very important role. Our classical results for the two processes are consistent with the numerical results.