Quantum coherent control of the photo\-electron angular distribution in bichromatic ionization of atomic neon

TL;DR

This paper explores how to coherently control the angular distribution of photo-electrons in neon during bichromatic ionization using theoretical models, considering practical experimental factors and the role of resonances.

Contribution

It introduces a comprehensive theoretical analysis of bichromatic neon ionization, incorporating effects of fine-structure, pulse parameters, and resonance conditions for quantum control.

Findings

Resonance conditions significantly influence control outcomes.

Non-resonant two-photon processes can enhance or diminish control.

Theoretical models align with potential experimental observations.

Abstract

We investigate the coherent control of the photo\-electron angular distribution in bichromatic atomic ionization. Neon is selected as target since it is one of the most popular systems in current gas-phase experiments with free-electron lasers (FELSs). In particular, we tackle practical questions, such as the role of the fine-structure splitting, the pulse length, and the intensity. Time-dependent and stationary perturbation theory are employed, and we also solve the time-dependent Schr\"odinger equation in a single-active electron model. We consider neon ionized by a FEL pulse whose fundamental frequency is in resonance with either $2p-3s$ or $2p-4s$ excitation. The contribution of the non\-resonant two-photon process and its potential constructive or destructive role for quantum coherent control is investigated.