In situ characterization of few-cycle laser pulses in transient absorption spectroscopy

TL;DR

This paper presents an ultrafast metrology method for in situ characterization of intense laser pulses in attosecond transient absorption spectroscopy, enabling precise measurement of pulse parameters and bound-state dynamics within the same experiment.

Contribution

The authors introduce a novel in situ measurement technique based on phase shifts in resonance, allowing simultaneous pulse characterization and dynamic analysis.

Findings

Pulse duration and intensity are determined in situ.

Time-dependent bound-state dynamics are quantified.

Method enhances accuracy of strong-field interaction studies.

Abstract

Attosecond transient absorption spectroscopy has thus far been lacking the capability to simultaneously characterize the intense laser pulses at work within a time-resolved quantum-dynamics experiment. However, precise knowledge of these pulses is key to extracting quantitative information in strong-field highly nonlinear light-matter interactions. Here, we introduce and experimentally demonstrate an ultrafast metrology tool based on the time-delay-dependent phase shift imprinted on a strong-field driven resonance. Since we analyze the signature of the laser pulse interacting with the absorbing spectroscopy target, the laser pulse duration and intensity are determined in situ. As we also show, this approach allows for the quantification of time-dependent bound-state dynamics in one and the same experiment. In the future, such experimental data will facilitate more precise tests of strong-field dynamics theories.