Fig. 3: Nonlinear optical (NLO) measurements of nonlinear activators.

a Schematic diagram of the double-balanced detection setup for measuring the NLO properties of integrated devices. Optical response results of few-layer MoTe₂ (b) under 1030 nm fs excitation and (c) under 515 nm fs excitation. The solid line is the fitted data. The nonlinear correlation between optical input and output of the activators (d) under 1030 nm fs excitation (e) under 515 nm fs excitation. The solid line represents the nonlinear activation function obtained from the result of Fig. 3b, c.