Extended Data Figure 3 : Nonlinear response saturation mechanism.

From: Giant nonlinear response from plasmonic metasurfaces coupled to intersubband transitions

Extended Data Figure 3

a, SH peak power output as a function of FF peak power squared (bottom axis) or peak intensity squared (top axis) at FF wavenumber 1,240 cm−1. Black curve, data for the pump laser operating with 400 ns pulses (same as used in the main text); red curve, data for the pump laser operating with 60 ns pulses. A slight difference in the SHG power for 60 ns and 400 ns FF input is attributed to slight changes in the pulse shape and detector response for 400 ns and 60 ns pulses. b, SH conversion efficiency versus FF peak power (bottom axis) or peak intensity (top axis) for FF wavenumber 1,240 cm−1 (red) and 1,280 cm−1 (blue). Straight lines show expected linear dependence of SH conversion efficiency on FF power for the cases in the absence of intensity saturation.