Figure 2
From: Ultrafast zero balance of the oscillator-strength sum rule in graphene
Transient dynamics of the low-energy THz oscillators.
(a) Negative THz field changes −ΔE(t)/E0 at different Δt are displayed as a function of the field delay t when the excited pump fluence is 40 μJ/cm2. (b) Pump-induced maximum changes in −ΔE(t)/E0 are shown as a function of the pump fluence. (c) Pump-induced real and imaginary conductivity changes Δσ(ω)/σ0 (red circles) are plotted as a function of Δt. For analysis, we used the thin-film conductivity formula of Δσ = −1/Z0(ΔE/E0)(nS + 1), where Z0 is the vacuum impedance and nS = 2.4 is the CVD diamond substrate refractive index. The measured conductivities were fitted using a Drude-like free-carrier model (black lines; see Supplementary Information).
