Fig. 2

Temperature- and fluence-dependent transient optical response. a ΔOD spectral map measured at 145 K with on-resonance infrared pump. b Transient kinetics at the wavelength that shows the strongest bleach signal (indicated by the dashed line in Fig. 1c), measured at different temperatures. c Transient spectra at 2 ns delay time measured at different temperatures. Legend in (c) applies to (b) as well. Pump fluence used in (b, c) was 0.45 mJ cm−2. d Fluence-dependent transient optical spectra at 2 ns delay time; inset: kinetics for different fluences appear nearly unchanged