Fig. 1. Schematic of the two-color pump–probe setup. Pulses with 50 fs duration at a 5 kHz repetition rate are used to drive the NOPA and white light generation. BS: beam splitter; SHG: second-harmonic generation; VA: variable attenuator; WLG: white-light generation; MLA: multi-channel lock-in amplifier.

Fig. 2. (a) Spectra of the different visible compressed wavelength pulses. The green line represents the spectra obtained by pumping the zinc chloride aggregate, and the red line represents the spectra for the PTB7-Th polymer in the subsequent experiments. The insert is the shortest compressed pulse duration according to the pink line (the black line is the duration measured, while the red line and blue fit are the Lorentzian fit and Gaussian fit, respectively). (b) Spectra of NIR. Insert is the stationary absorption spectrum of the PTB7-Th polymer (red line).

Fig. 3. (a) Two-dimensional pattern of the, different absorbances (ΔA), which are dependent on the time delay from −200 to 2800 fs in the whole probe spectral region (670–760 nm); (right) time trace of different absorbance rates. (b) Two-dimensional pattern of the different absorbances (ΔA) dependent on the time delay from −0.4 to 100 ps in the whole probe spectral region (960–1040 nm); (right) time trace of different absorbances.