Extended Data Fig. 4: Determination of the pump–probe overlap.
From: Origin of strong-field-induced low-order harmonic generation in amorphous quartz
a, Variation of the central probe wavelength as a function of the number of pump–probe delay increments (one increment represents a delay of ≈6.7 fs). The shift of the central wavelength is due to cross-phase modulation and shows a maximum when pump and probe overlap in the focal region. b, projection of the n = 1 harmonic on the delay axis. The grey dotted curve was obtained by direct integration of the data shown in a.
