Photoionization with rescattering: Quantum theory and the semiclassical approach

We compare the spectral-angular distributions of photoelectrons in a high-e nergy plateau of above-threshold ionization calculated in the tunneling lim it within the framework of a semiclassical three-step model and obtained by the saddle-point method. It is demonstrated that both procedures of calcul ations give mathematically equivalent results, adequately describing the di stribution of photoelectrons within the range predicted by the three-step m odel, but become inapplicable near the boundaries of this range.