Strong-Field Tunneling Ionization Rate Based on Landau–Dykhne Transition Theory

Abstract

Abstract: The ionization of a helium atom and helium like atoms in a linearly polarized low-frequency laser field is investigated by the Landau–Dykhne transition theory. The tunneling rate’s formula for the trigonometric pulse envelope linearly polarized laser field is obtained, by taking into account electrons correlation in the ground state and the Coulomb correction. The obtained curve is compared with the Ammosov–Delone–Krainov theory. The curve displays a good flow but overestimates the Ammosov–Delone–Krainov one. Additionally, we analyzed different wavelengths, as well as the influence of the corrected ionization potential by including the ponderomotive shift. Our analysis shows that the inclusion of the additional terms in the ionization potential decreases rate, and that the properties of the beam shape has an effect on the ionization rate. We also find that the ionization rate is very sensitive to the value of laser wavelength (frequency) and the parabolic coordinate.