Fig. 1: Schematic of the pump-probe experiment and ISRS map measured with an ultrabroadband UV probe.

a Sketch of the transient absorption set-up. A few-cycle NIR pump, which spans from 500 to 975 nm, and a UV probe pulse are propagated in vacuum and focused on a thin liquid jet in a noncollinear geometry. The UV probe is then dispersed on single shot spectrometer and the differential absorbance signal is recorded as a function of the probe wavelength and the pump-probe time delay. b UV probe static spectrum (top) and colour map of the measured transient absorption signal as a function of the pump-probe time delay (bottom). The large bandwidth of our UV pulses allows to simultaneously probe the dynamics in different spectral regions. In particular, the blue (left) and red (right) sides of the transient absorption exhibit out-of-phase oscillations between positive and negative values.