# Coulomb-induced ionization time lag after electrons tunnel out of a barrier

## TL;DR

This paper investigates how the Coulomb potential causes a significant time lag between an electron tunneling out of an atomic barrier and becoming free, impacting strong-field phenomena and attosecond measurement techniques.

## Contribution

It reveals that Coulomb effects induce a large ionization time lag, providing new insights into strong-field physics and guiding attosecond measurement improvements.

## Key findings

- Coulomb effect causes a time lag over a hundred attoseconds.
- The time lag significantly influences high-harmonic generation.
- Implications for improving attosecond measurement accuracy.

## Abstract

After electrons tunnel out of a laser-Coulomb-formed barrier, %formed by the strong laser field and the atomic Coulomb potential, the movement of the tunneling electron can be affected by the Coulomb tail. We show that this Coulomb effect induces a large time difference (longer than a hundred attoseconds) between the exiting time at which the electron exits the barrier and the ionization time at which the electron is free. This large time difference has important influences on strong-field processes such as above-threshold ionization and high-harmonic generation, with remarkably changing time-frequency properties of electron trajectories. Some semi-quantitative evaluations on these influences are addressed, which provide new insight into strong-field physics and give important suggestions on attosecond measurements.