Attosecond Ionization Time Delays in Strong-Field Physics

TL;DR

This review discusses recent laser-based techniques for measuring attosecond-scale ionization delays in atoms and molecules, highlighting advances in experimental methods and a novel hybrid approach for tunneling ionization analysis.

Contribution

It provides a comprehensive overview of attosecond timing techniques and introduces the backpropagation method for characterizing tunneling ionization dynamics.

Findings

Advances in laser techniques enable attosecond resolution of ionization processes.

The backpropagation method offers a new way to analyze tunneling ionization.

Continued technological progress will allow exploration of faster electronic dynamics.

Abstract

Electronic processes within atoms and molecules reside on the timescale of attoseconds. Recent advances in the laser-based pump-probe interrogation techniques have made possible the temporal resolution of ultrafast electronic processes on the attosecond timescale, including photoionization and tunneling ionization. These interrogation techniques include the attosecond streak camera, the reconstruction of attosecond beating by interference of two-photon transitions, and the attoclock. While the former two are usually employed to study photoionization processes, the latter is typically used to investigate tunneling ionization. In this Topical Review, we briefly overview these timing techniques towards an attosecond temporal resolution of ionization processes in atoms and molecules under intense laser fields. In particular, we review the backpropagation method, which is a novel hybrid quantum-classical approach towards full characterization of tunneling ionization dynamics. Continued advances in the interrogation techniques promise to pave the pathway towards the exploration of ever faster dynamical processes on an ever shorter timescale.