Attosecond tunneling time measurements through momentum squeezing in strong field ionization

TL;DR

This paper demonstrates that the momentum profile of an electron wavepacket tunneling through a potential barrier reveals the tunneling time, providing a self-probing method to measure attosecond-scale tunneling durations in strong field ionization.

Contribution

It introduces a novel interpretation of the attoclock setup, linking electron momentum profiles to tunneling times, and confirms the order of hundreds of attoseconds through simulations.

Findings

Tunneling times are on the order of hundreds of attoseconds.

Electron momentum profiles encode tunneling time information.

The method aligns with previous theoretical predictions.

Abstract

Tunneling of a particle through a potential barrier is a fundamental physical process and a major thought-provoking outcome of quantum physics. It is at the basis of multiple scientific and technological advances and strongly influences both the structuring and the dynamics of matter at the microscopic scale. Without a classical counterpart, it defies our intuitive perception and understanding of the motion of a particle. Thus, the temporal characterization of tunneling, typically in terms of the time spent "under the barrier", referred to as tunneling time, raises several debates and questions on its interpretation and measurability. Here we show that an electron wavepacket tunneling out of an atom through the potential barrier induced by a strong electric field, carries in its momentum profile the value of the corresponding tunneling time, in a self-probing manner. In a revisited interpretation of the attoclock setup, we view a circularly polarized light pulse as a temporal prism which maps the barrier configuration, and hence the tunneling dynamics, onto different photoelectron ejection directions. From our simulations, we find that tunneling times in the infrared regime are of the order of hundreds of attoseconds, in agreement with previous theories.