Figure 3
Transient absorption dynamics measured at probe wavelengths λ near 1300 nm (obtained by integrating the signal from 1200 nm to 1400 nm) for excitation wavelengths of λ*=800 nm (a) and λ*=400 nm (b) for three different pump pulse fluences and demonstrating the single-photon-absorption regime. The dashed lines are single- (a) and double-exponential (b) fits to the data. The double-exponential decay at the λ*=400 nm excitation wavelength is the fingerprint of CM. The insets show the maximum amplitude of the TA transients (A) and its ratio to the amplitude of the single exciton decay tail (A/B) as a function of the absorbed photons fluence (see text for explanation). CM, carrier multiplication; OD, optical density; TA, transient absorption.
