Ionization branching ratio control with a resonance attosecond clock

TL;DR

This paper explores real-time monitoring and control of autoionizing states in helium using XUV-pump IR-probe experiments, revealing interference patterns and quantum beats in ionization yields.

Contribution

It demonstrates the potential to control ionization channel yields by simulating attosecond-resolved experiments on autoionizing states.

Findings

Interference fringes observed in photoelectron angular distributions.

Quantum beats in ion yields are out-of-phase.

Decay of superpositions occurs via electron ejection in bursts.

Abstract

We investigate the possibility to monitor the dynamics of autoionizing states in real time and control the yields of different ionization channels in helium by simulating XUV-pump IR-probe experiments focused on the N=2 threshold. The XUV pulse creates a coherent superposition of doubly excited states which is found to decay by ejecting electrons in bursts. Prominent interference fringes in the photoelectron angular distribution of the $2s$ and $2p$ ionization channels are observed, along with sizable out-of-phase quantum beats in the yields of the corresponding parent ions.