Schematic of the experimental setup. The amplifier outputs 50-fs pulses at 800 nm with a 1-kHz repetition rate and an average power of 0.8 W. OPA 1 generates 640- and 320-nm pulses with average powers of 20 and 1 mW, respectively. OPA 2 generates 585-nm pulses with an average power of 5 mW. Other components include a chopper (CH), delay stages (D1, D2, and D3), a spherical mirror (SM), a set of attenuation filters (AF), a monochromator (MH), and a PMT.