Figure 1. Partially coherent spectrography with ultrashort XUV pulses.

(a) Schematic of a FROG-CRAB measurement in the presence of decoherence, here due to shot-to-shot XUV pulse fluctuations. (b) Photoelectron spectra obtained for various delays between the pulse mixture and the 800-nm laser pulse (duration 3-fs FWHM, intensity 8 TW cm⁻²) represented by its vector potential A(t). Each colour (red, green and blue) corresponds to a pure ultrashort pulse. (c) Wigner function W_P (ω, t) and the associated energy spectrum of the electron wave packet without (left panel) and with (right panel) laser pulse at a given delay.