Universal in-line waveform characterization using arbitrary nonlinear responses

Contemporary schemes for waveform-resolved characterization are constrained by setup-specific requirements, which severely limit their adaptability and fail to establish standard procedures for routine in-line diagnostics. This work reports a comprehensive experimental demonstration that relative yield measurements from a wide variety of media and nonlinear observables, combined with our family of open-source reconstruction algorithms (CRIME, twinCRIME, and lazyCRIME), allow for robust waveform retrieval with attosecond accuracy on a standard workstation in just minutes. We have further adapted this framework to multiple configurations-including non-invasive, simultaneous waveform characterization during an attosecond transient absorption spectroscopy (ATAS) experiment-showcasing the low-cost and non-intrusive nature of the new pulse characterization approach. Together, this work establishes an easy-to-implement universal characterization scheme for in-line diagnostics of ultrashort pulses that is readily accessible to the broader ultrafast science community.