Displacement effect in strong-field atomic ionization by an XUV pulse

TL;DR

This paper investigates how non-zero displacement in XUV pulses affects strong-field atomic ionization, revealing extreme sensitivity to pulse parameters and suggesting broad applicability across atomic systems.

Contribution

It demonstrates that non-zero displacement in XUV pulses significantly influences ionization, highlighting the importance of pulse shape and phase in strong-field processes.

Findings

Ionization is highly sensitive to pulse ramp-on/off profiles.

Carrier envelope phase significantly affects ionization outcomes.

Effect observed in hydrogen and lithium at high intensities.

Abstract

We study strong-field atomic ionization driven by an XUV pulse with a non\-zero displacement, the quantity defined as the integral of the pulse vector potential taken over the pulse duration. We demonstrate that the use of such pulses may lead to an extreme sensitivity of the ionization process to subtle changes of the parameters of a driving XUV pulse, in particular, the ramp-on/off profile and the carrier envelope phase. We illustrate this sensitivity for atomic hydrogen and lithium driven by few-femto\-second XUV pulses with intensity in the $\rm 10^{14}~W/cm^2$ range. We argue that the observed effect is general and should modify strong-field ionization of any atom, provided the ionization rate is sufficiently high.