Predictable third harmonic generation in GaAs metasurfaces through group theory inverse design of meta-atoms

Journal Article · Fri Dec 19 00:00:00 EST 2025 · Optics Letters

DOI:https://doi.org/10.1364/OL.583903· OSTI ID:3012767

Aoueille, Andrew; Hurley, Noah; BUSTAMANTE, EDGAR; Martinez, Noel; Reinke, Charles; El-Kady, Ihab; Lin, Yuankun

Here we report the group theory-based inverse design of meta-atoms for a dielectric metasurface in GaAs with predictable optical linear response and third harmonic generation (THG). Six sharp Fano resonances have been observed with a corresponding polarization dependence as predicted by group theory and the meta-atom’s symmetry in the D2h point group. THG has been observed for two modes under x-polarization excitation and one mode for y-polarization, in agreement with theoretical symmetry predictions. The polarization-dependent THG aspect ratio was observed to reach as high as 108. Through strategic structural or symmetry-preserving perturbations, it was shown that the THG can be enhanced or reduced by a factor of 7. The highest THG conversion efficiency was estimated to be 3.1×10-7 at the pump intensity of 1.51 MW/cm2. This high THG conversion efficiency indicates that our group theory approach to modal engineering opens a new path towards optical nonlinearity tuning in dielectric metasurfaces.

• Research Organization: University of North Texas
• Sponsoring Organization: National Nuclear Security Administration
• Grant/Contract Number: NA0004114
• OSTI ID: 3012767
• Journal Information: Optics Letters, Journal Name: Optics Letters; ISSN 1539-4794; ISSN 0146-9592
• Publisher: Optica Publishing Group
• Country of Publication: United States
• Language: English