Extended Data Fig. 7. Spectral and temporal properties of the ω − 2ω trefoil pump pulses.

Subplot a shows the measured laser spectra recorded after the interferometer, right before the focusing objective to give an accurate representation of the laser pulses used. The laser pulses are picked off from the same region for frequency-resolved optical gating (FROG) retrieval. The retrieved spectra and temporal profile along with their phases are shown in subplots b,c, respectively. It suggests the pulse durations of about 26.1 and 48.0 fs for ω and 2ω, respectively.