Backward phase-matched second-harmonic generation from stacked metasurfaces

TL;DR

This paper demonstrates phase-matched second-harmonic generation using stacked metasurfaces with a novel phase engineering mechanism, achieving significant efficiency enhancement and opening pathways for advanced nonlinear optical applications.

Contribution

Introduces a new phase engineering approach for phase-matched SHG in stacked metasurfaces, enabling backward direction SHG with high efficiency.

Findings

Up to 25-fold increase in SHG efficiency with five metasurfaces

Phase engineering enables backward phase-matched SHG

Potential for higher efficiencies with complex wavefronts

Abstract

We demonstrate phase-matched second-harmonic generation (SHG) from three-dimensional metamaterials consisting of stacked metasurfaces. To achieve phase matching, we utilize a novel mechanism based on phase engineering of the metasurfaces at the interacting wavelengths, facilitating phase-matched SHG in the unconventional backward direction. By stacking up to five metasurfaces, we obtain the expected factor of 25 enhancement in SHG efficiency. Our results motivate further investigations to achieve higher conversion efficiencies also with more complex wavefronts.