Phase- and intensity-dependence of the cutoffs in two-color high-harmonic generation

We investigate high-harmonic generation with two driving fields of commensu rate frequencies with emphasis on the influence of their relative phase and intensities. We compare numerical calculations based on the solution of th e one-dimensional time-dependent Schrodinger equation to results derived in the context of the semiclassical three-step model. We concentrate on how t he relative phase and the relative intensities affect the maximal-energy tr ajectories of the returning electron and, consequently, the harmonic spectr a. Our results show there is no analog of the simple cutoff law pertinent t o the monochromatic case.