Resonantly enhanced second-harmonic generation using III-V semiconductor all-dielectric metasurfaces

TL;DR

This paper demonstrates resonantly enhanced second-harmonic generation in GaAs dielectric metasurfaces, achieving significant efficiency improvements through nanostructuring and resonant effects, with potential applications in nonlinear optics.

Contribution

First demonstration of resonantly enhanced SHG using GaAs dielectric metasurfaces with high conversion efficiency and detailed analysis of nonlinear mechanisms.

Findings

SHG enhancement factors up to 10^4

Absolute nonlinear conversion efficiency of ~2x10^-5

Both bulk and surface nonlinearities contribute to SHG

Abstract

Nonlinear optical phenomena in nanostructured materials have been challenging our perceptions of nonlinear optical processes that have been explored since the invention of lasers. For example, the ability to control optical field confinement, enhancement, and scattering almost independently, allows nonlinear frequency conversion efficiencies to be enhanced by many orders of magnitude compared to bulk materials. Also, the subwavelength length scale renders phase matching issues irrelevant. Compared with plasmonic nanostructures, dielectric resonator metamaterials show great promise for enhanced nonlinear optical processes due to their larger mode volumes. Here, we present, for the first time, resonantly enhanced second-harmonic generation (SHG) using Gallium Arsenide (GaAs) based dielectric metasurfaces. Using arrays of cylindrical resonators we observe SHG enhancement factors as large as 104 relative to unpatterned GaAs. At the magnetic dipole resonance we measure an absolute nonlinear conversion efficiency of ~2X10^(-5) with ~3.4 GW/cm2 pump intensity. The polarization properties of the SHG reveal that both bulk and surface nonlinearities play important roles in the observed nonlinear process.