Channel-closing effects in high-order above-threshold ionization and high-order harmonic generation

摘要: The strong-field approximation, amended so as to allow for rescattering, is used calculate high-order above-threshold ionization (ATI) spectra. single-active-electron binding potential modelled by a zero-range potential. emphasis on enhancements of groups ATI peaks that occur sharply defined laser intensities. are traced multiphoton resonance with the ponderomotively upshifted continuum threshold. Good agreement both experimental data and numerical simulations using three-dimensional time-dependent Schrodinger equation an optimized one-electron observed. physical reason close results two, apparently different, models discussed. For quantitative experimentally observed positions resonances, `effective' threshold has be introduced. effects focal averaging evaluated Resonant enhancement harmonic generation also considered.