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Precise knowledge of the structure of ultrashort light pulses simultaneously in space and time is fundamental for their successful applications. To this end, various techniques have been developed that determine the spatio-spectral properties and couplings. Here, we report on a simple, enhanced version of a spatio-spectral metrology approach termed simplified INSIGHT. Furthermore, we compare two commonly used spatio-spectral diagnostic methods ‘HASO multispectral’ and ‘INSIGHT’. As a source, we utilize a non-collinear optical parametric amplifier that supports few-optical-cycle pulses with an artificially introduced spatio-spectral coupling. While both techniques successfully resolve the introduced aberration, each has distinct practical advantages and disadvantages, which we investigate and discuss. Finally, we propose a practical way to assess the correctness of spatio-temporal characterization results.

Ultrahigh peak-power laser systems with pulse durations of tens of femtoseconds are widely used as drivers for compact sources of particles and secondary radiation. Conversely, lasers with shorter (a few femtoseconds) pulse durations and lower peak powers enable the generation of isolated attosecond light pulses to study nature with unparalleled temporal resolution. Here we report an enhanced optical parametric chirped pulse amplifier system that produces light pulses with a peak power of about 100 TW and a pulse duration as short as 4.3 fs with full waveform control. Coherent field synthesis generates a broadband spectrum, spanning from the visible to the near infrared, through three cascaded amplification stages, each housing two optical parametric amplifiers that sequentially boost complementary spectral regions. The resulting light transients are waveform-stabilized to <300 mrad and focused to an intensity of 1021 W cm−2 and exhibit an outstanding high dynamic range in temporal contrast. Together, these characteristics render the system well suited for demanding relativistic laser–plasma experiments. Utilizing temporal super-resolution, the pulses are shortened to sub-4-fs duration. This platform is dedicated to advancing the frontiers of attosecond electron and X-ray sources.