Ionisation dynamics through a Fano resonance: Time domain interpretation of spectral amplitudes

TL;DR

This paper analytically and numerically validates a conjecture used in experiments to reconstruct Fano autoionisation dynamics from spectral amplitudes, establishing its validity within Fano formalism and beyond.

Contribution

It provides a rigorous analytical proof of the conjecture and derives a general condition for its validity outside the Fano case.

Findings

Analytical proof of the conjecture within Fano formalism

Numerical validation on model atoms with autoionising states

Derivation of a general validity condition beyond Fano

Abstract

We investigate a conjecture used in recent experiments to reconstruct the complete dynamics of Fano autoionisation processes out of measured spectral amplitudes [Gruson et al, Science 354 734 (2016); Beaulieu el al, Science 358 1288 (2017); Busto et al, J. Phys. B: At. Mol. Opt. Phys. 51 044002 (2018)]. The validity of the conjecture is established analytically within the formalism of Fano, and tested numerically on model atoms displaying adjustable autoionising states. A general condition for which the conjecture is valid, beyond the Fano case, is then derived.