Figure 3:

Sum frequency generation from Au/CuS bilayer films by dual-beam pumping. (a) A simplified diagram of the experimental dual-beam setup. BS, beam splitter; HS, harmonic separator, BPF = 350 nm bandpass filter. Red line is 1050 nm fundamental beam, green is 525 nm (2ω) beam, and blue 350 nm (3ω) beam. (b) Intensity of THG output generated by hybrid films as a function of fundamental beam intensity after beam splitter for different R:T ratio beam splitter: 100:0 (red—power of 2ω 0 μW), 70:30 (blue—power of 2ω beam 185 μW), 50:50 (orange—power of 2ω 300 μW). (c) Double-logarithmic plots of THG intensity as a function of pump laser intensity for the data of (b).