Fig. 7
Lifetime density analysis of the ultrafast response. a Lifetime density map (LDM) fitted to the differential absorbance data in Fig. 6 and displayed on a log–log scale. Multiple distinct peaks can be observed spanning the entire range of lifetimes at each resonance. b, c Comparison of the decay-associated spectra (DAS) corresponding to fast, intermediate (int), and slow nonthermal e–e scattering and thermal e–ph scattering at the multipolar and gap plasmon resonances. The small fluctuations at 1100 nm are artifacts from residual pump scatter. d–g Lifetime traces of the LDM (blue circles) at the same wavelengths as the kinetics in Fig. 6e. Contributions from nonthermal electron–electron scattering and thermal electron–phonon scattering are indicated (shaded regions) along with the total fitted response (red line). The gray regions are contributions from phonon–phonon scattering (~10 ps) and semi-infinite decay due to lattice heating (~100 ps)
