Non-exponential tunneling ionization of atoms by an intense laser field

TL;DR

This paper explores the non-exponential, power-law decay behavior in tunneling ionization of atoms under intense laser fields, challenging traditional exponential decay models and highlighting new long-time dynamics.

Contribution

It introduces the concept of non-exponential tunneling ionization in atoms driven by strong low-frequency laser fields, expanding understanding of decay processes at long times.

Findings

Decay follows a ~1/t power-law at long times

Non-exponential depletion occurs due to energy spectrum cutting

Applicable to strong low-frequency electromagnetic fields

Abstract

We discuss the possibility of non-exponential tunneling ionization of atoms irradiated by intense laser field. This effect can occur at times, which are greater than the lifetime of a system under consideration. The mechanism for non-exponential depletion of an initial quasi-stationary state is the cutting of the energy spectrum of final continuous states at long times. We first consider the known examples of cold emission of electrons from metal, tunneling alpha-decay of atomic nuclei, spontaneous decay in two-level systems and the single-photon atomic ionization by a weak electromagnetic field. The new physical situation discussed is tunneling ionization of atoms by a strong low-frequency electromagnetic field. In this case the decay obeys ~1/t power-law dependence on the (long) interaction times.