Fig. 6. Differential transmission spectrum at 77 K of the XLE range at (a) 5 ps (c) 250 ps delay, showing long lived thermalization dynamics: differences between resonant (red line) and non-resonant (blue line) excitation are still found after hundreds of picoseconds. (b and d) Dynamics at the spectral position of (b) Π1 and d) Γ2 respectively on the red and blue side of the resonant pump, showing contributions of opposite sign for tens (Π1) and hundreds of ps (Γ2).
