Effect of the excited states on the disappearance of the dynamical interference from the atomic two-photon ionization

By solving the three-dimensional time-dependent Schrödinger equation accurately, the ionization process of a hydrogen atom under the action of a laser pulse with a frequency of 0.3 a.u. was investigated. The study revealed that with the increase of the driving laser intensity, the ionization probability of the atom declined after rapidly increasing, exhibiting a characteristic of ionization suppression. It is noteworthy that the dynamic interference disappears in a certain range of laser intensities in the ionization suppression zone. Through the analysis of the excited state of the system, it is found that the reason for the disappearance of the dynamic interference phenomenon is that in addition to the direct ionization of electrons from the ground state, there is also the excitation to the excited state first and then ionized from the excited state, the laser intensity for which has not yet reached the ionization suppression requirement in the meantime.