Fig. 4: Simulated and experimental differential transmittance ΔT(t)/T0 and CP spectra.

a Simulated differential transmittance ΔT(t)/T0 of the A1′(Γ) mode (upper panel), LA(K) mode (middle panel) and combination of the LA(K) and A1′(Γ) modes (bottom panel). Simulation parameters are shown in the insets. b Comparison of experimental and simulated CP spectra. The latter was obtained from the Fourier transformation of the differential transmittance ΔT(t)/T0 of the combination of LA(K) and A1′(Γ) modes (bottom panel of a).