Relativistic non-dipole effects in strong-field atomic ionization at moderate intensities

TL;DR

This study investigates relativistic non-dipole effects in strong-field atomic ionization using high-resolution measurements and relativistic modeling, revealing counter-intuitive electron momentum shifts at moderate laser intensities.

Contribution

It provides the first detailed experimental and theoretical analysis of relativistic non-dipole effects in strong-field ionization at moderate intensities.

Findings

Observation of counter-intuitive peak shifts in electron momentum distributions.

Excellent agreement between experimental data and relativistic 3D Dirac equation simulations.

Identification of non-dipole effects influencing electron dynamics at 10^14 - 10^15 W/cm^2.

Abstract

We present a detailed experimental and theoretical study on the relativistic non-dipole effects in strong-field atomic ionisation by near-infrared linearly-polarised few-cycle laser pulses in the intensity range 1014 -1015 W/cm2. We record high-resolution photoelectron momentum distributions of argon using a reaction microscope and compare our measurements with a truly ab-initio fully relativistic 3D model based on the time-dependent Dirac equation. We observe counter-intuitive peak shifts of the transverse electron momentum distribution in the direction opposite to that of laser propagation as a function of laser intensity and demonstrate an excellent agreement between experimental results and theoretical predictions.