Backward Phase-Matched Second-Harmonic Generation from Stacked Metasurfaces

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. Stacking up to five metasurfaces,we obtain a phase-matched SHG signal, which scales superlinearly with the number of layers. Our results motivate further investigations to achieve higher conversion efficiencies also with more complex wave fronts.

Automated summary

This study demonstrates phase-matched second-harmonic generation (SHG) from three-dimensional metamaterials consisting of stacked metasurfaces. By utilizing phase engineering of metasurfaces at interacting wavelengths, they achieved phase-matched SHG in the unconventional backward direction, with SHG signal scaling superlinearly with the number of layers. Their results inspire further research to achieve higher conversion efficiencies and address more complex wave fronts.