Figure 3:

THG by Na-based thin films. (a, e) Dependence of the FW intensity of the THG signal $I_{\text{THG}}^T$ over the pump wavelength λ and incidence angle θ for fixed pump intensity I ₀ = 100 GW/cm². (b, c, f, g) Dependence of $I_{\text{THG}}^T$ over the pump incidence angle θ for (b, f) fixed pump wavelength λ = 630 nm and several intensities I ₀ = 50, 75, 100 GW/cm², and (c, g) fixed pump intensity I ₀ = 100 GW/cm² and several wavelengths λ = 615, 630, 650 nm [highlighted by the gray shaded area in (a, e)]. (d, h) Dependence of $I_{\text{THG}}^T$ over the pump intensity I ₀ for fixed incidence angle θ = 11° and several wavelengths λ = 615, 630, 650 nm [highlighted by the gray shaded area in (a, e)]. All plots refer to either (a–d) TM or (e–h) TE polarization of the pump field for fixed thin film thickness d = 300 nm.