Аннотация:We present the results of the theoretical study of the high-order harmonic
generation (HHG) in atomic gases. It is shown that the photoemission spectra exhibit
unusual behavior when the laser field strength approaches near-atomic values.
In subatomic field strength the cut-off frequency increases linearly with laser pulse
intensity. However, when the field strength approaches near-atomic region firstly
cut-off frequency slows down and then saturates. To interpret such kind of photoemission
spectrum behavior we have proposed the light-atom interaction theory
based on the use of eigenfunctions of boundary value problem for “an atom in the
external field” instead of the traditional basis of the “free atom” eigenfunctions