Evolutionary design of two-dimensional material Fabry–Perot structures for enhanced second harmonic generation

Abstract The integration of two-dimensional (2D) materials with resonant photonic structures is seen as a promising direction for enhancing its nonlinear optical response. design such heterogeneous has often relied on multi-parameter sweeps to determine the optimized dimensions structure that results in good resonance characteristics, absence 2D material. Such an approach computationally intensive and may not necessarily result efficient generation or collection signals from designed structure. Here, we report hybrid-genetic optimization (HGA) based experimental demonstration second harmonic (SHG) enhancement Fabry–Perot single double multilayer gallium selenide (GaSe) flakes bottom silicon dioxide, index matched polymethyl methacrylate spacer/encapsulation layers. HGA technique utilized here speeds up cavity by 8.8 89-times GaSe when compared full parameter-sweep, measured SHG 128- 400-times, respectively, reference sample composed layer thickness 300 nm dioxide layer. conversion efficiencies obtained are 1–2 orders magnitude higher than previous reports material integrated metasurfaces Bragg cavities.