Multiply-resonant Second-harmonic Generation using Surface Lattice Resonances in Aluminum Metasurfaces

TL;DR

This paper demonstrates how tilting aluminum nanoparticle arrays supporting surface lattice resonances can achieve multiply-resonant conditions, significantly enhancing second-harmonic generation efficiency in nonlinear metasurfaces.

Contribution

It introduces a method to induce multiple resonances in aluminum metasurfaces via tilting, improving nonlinear optical responses by leveraging surface lattice resonances.

Findings

Tilted metasurfaces exhibit multiple resonances for pump and second-harmonic wavelengths.

Measured second-order susceptibility of 0.40 pm/V in aluminum metasurfaces.

Surface lattice resonances enhance second-harmonic generation efficiency.

Abstract

Nonlinear metamaterials show potential for realizing flat nonlinear optical devices but generally lack 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.