Excited-state resonance tunneling in strong-field ionization

Abstract

We study the tunneling dynamics of a system with two bound states. We find that the system can be effectively described by a two-level leakage cavity model, with which we can reproduce the dynamics of tunneling ionization. It shows that tunneling via the excited-state resonance dominates over the ground-state tunneling within the field strength considered, where the electron prefers jumping to the excited-state resonance channel first and then tunneling out. Moreover, several key parameters of the system naturally emerge in our two-level model. Especially, one of the parameters is the physical correspondence of the tunneling time obtained from the ground-state tunneling.