Fano line shape metamorphosis in resonant two-photon ionization

TL;DR

This paper explores how the Fano resonance line shape in two-photon ionization can be transformed from asymmetric to symmetric, enabling direct measurement of resonance lifetimes without high energy resolution.

Contribution

It introduces a method to manipulate Fano profiles in two-photon ionization, allowing lifetime determination through line shape metamorphosis.

Findings

Fano line shape can be transformed into a Gaussian profile.

Line shape transformation enables direct lifetime measurement.

Method applicable across various quantum systems.

Abstract

Two-photon atomic ionization driven by time-locked XUV and IR pulses allows to study dynamics of Fano resonances in time and energy domains. Different time evolution of the two interfering pathways leading to a Fano resonance can be exploited to turn the Fano profile of the two-photon XUV/IR ionization into a symmetric Gaussian once the directly ejected photoelectron leaves the parent ion and cannot any longer absorb an IR photon. This line shape transformation allows for the direct determination of the resonant lifetime from the spectroscopic measurements without need for an extremely fine energy resolution. Ubiquitous nature of Fano resonances makes this determination a universal tool in diverse quantum systems ranging from nuclei to nano-fabricated solids.