In situ characterization of few-femtosecond laser pulses by learning from first-principles calculations

The accurate characterisation of ultrashort laser pulses is crucial for their application in the field of ultrafast laser spectroscopy. In particular, in-situ methods are challenging to be implemented but highly desirable, enabling the measurement of the laser properties in the region of interaction with
the target under study.

An interdisciplinary team of scientists from the Center for Free-Electron Laser Science (CFEL) at DESY now proposed a novel method for the in-situ characterisation of intense few-fs laser pulses by employing the strong-field ionisation of rare gas atoms. The researchers combined firstprinciples
calculations and and a novel machine-learning algorithm, called vector space Newton interpolation cage (VSNIC), to reconstruct from a strong-field autocorrelation pattern for an unknown pulse the pulse length and spectral width by narrow margins.

The team includes scientists from the attosecond science group led by Francesca Calegari and the theory division led by Robin Santra. The results are reported in the journal Optics Letters, and the paper has been highlighted as an Editor's Pick.

Reference:

Otfried Geffert, Daria Kolbasova, Andrea Trabattoni, Francesca Calegari, and Robin Santra, "In situ characterization of few-femtosecond laser pulses by learning from first-principles calculations" Opt. Lett. 47, 3992-3995 (2022). DOI: https://doi.org/10.1364/OL.460513