Ionization rate for circularly polarized laser fields with modified ionization potential included

Abstract

During the ionization of atoms with low-frequency laser fields, tunneling ionization occurs when the Keldysh parameter γ ≪ 1. One of the most widely used theories is the Ammosov–Delone–Krainov (ADK) theory, which was developed for both linearly and circularly polarized laser fields. This paper studies the influence of modified ionization potential on ionization rate in the ADK theory for the case of a circularly polarized laser field. The studied atoms are K, Na, Li and Cs; they are ionized by CO2 laser in the intensity regime between 1014 and 1016 W cm−2. It is found that ionization rates of atoms with similar values of ionization potential behave in a similar manner; also, the influence of modified ionization potential on ionization rates is much stronger at higher laser intensities.