Photoionization of a strongly polarizable target

TL;DR

This paper shows that the angular distribution of photoelectrons from a strongly polarizable target can significantly deviate from conventional predictions due to laser-induced dipole effects, especially near plasmon resonances.

Contribution

It introduces a new understanding of photoelectron angular distributions considering dynamic polarizability effects within the dipole approximation.

Findings

Significant deviations in photoelectron distribution profiles near plasmon resonances.

Laser fields of low intensity can induce strong modifications in ionization characteristics.

The effect depends on the target's polarizability, geometry, and laser parameters.

Abstract

We demonstrate that the angular distribution of photoelectrons from a strongly polarizable target exposed to a laser field can deviate noticeably from the prediction of conventional theory. Even within the dipole-photon approximation the profile of distribution is modified due to the action of the field of alternating dipole moment induced at the residue by the laser field. This effect, being quite sensitive to the dynamic polarizability of the residue and to its geometry, depends also on the intensity and frequency of the laser field. Numerical results, presented for sodium cluster anions, demonstrate that dramatic changes to the profile occur for the photon energies in vicinities of the plasmon resonances, where the effect is enhanced due to the increase in the residue polarizability. Strong modifications of the characteristics of a single-photon ionization process can be achieved by applying laser fields of comparatively low intensities $I_0 \sim10^{10}-10^{11}$ W/cm$^2$.