Multiply-resonant second-harmonic generation using surface lattice resonances in aluminum metasurfaces

Nonlinear metamaterials show potential for realizing flat nonlinear optical devices but are generally lacking in terms of achievable conversion efficiencies. Recent work has focused on enhancing nonlinear processes by utilizing high quality factor resonances, such as collective responses known as surface lattice resonances (SLRs) taking place in periodic metal nanoparticle arrays. Here, we investigate how the dispersive nature of SLRs affects the nonlinear responses of SLR-supporting metasurfaces. Particularly, we measure second-harmonic generation from aluminum nanoparticle arrays and demonstrate that by tilting the sample along two orthogonal directions, the sample can be made multiply-resonant for several pump and second-harmonic signal wavelength combinations. Characterized metasurfaces are estimated to exhibit a second-order susceptibility value of 0.40 pm/V, demonstrating aluminum as a potential material for nonlinear metasurfaces. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

Nonlinear metamaterials have the potential for flat nonlinear optical devices, but their conversion efficiencies are generally low. Recent research has focused on enhancing nonlinear processes by utilizing high quality factor resonances, such as surface lattice resonances (SLRs). The study investigates the dispersive nature of SLRs and its effect on the nonlinear responses of SLR-supporting metasurfaces. Experimental results show that tilting the sample along two orthogonal directions can achieve multiple resonances for different pump and second-harmonic signal wavelengths. The characterized metasurfaces exhibit a second-order susceptibility value of 0.40 pm/V, suggesting aluminum as a potential material for nonlinear metasurfaces.