Figure 1.

The response coefficients (a) |S₁(ω)| and (b) |S₂(ω)| for relaxation parameters Γ = 0.5 meV and 33 meV at the temperatures T = 0 and 300 K and chemical potential μ = 0.3 eV. The black dashed curves are the intraband contributions from Eq. (17). (c) Shows the chemical potential dependence of |S₁(ω)| at ħω = 0.3 eV for the same relaxation parameters and temperatures. The right y-axis shows the second order susceptibility for light that propagates parallel to the graphene sheet.