Moretti, G. Q.G. Q.MorettiTilmann, B.B.TilmannTittl, AndreasAndreasTittlCorts, E.E.CortsMaier, S.S.MaierBragas, A. V.A. V.BragasGrinblat, G.G.Grinblat2026-03-262026-03-262023-0713th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2023https://hdl.handle.net/11420/62422A metasurface of Gallium Phosphide on glass with a robust design enables high-quality factor (Q) modes, arising from the concept of quasi bound states in the continuum (QBICs). The high enhancement of the incident electric field is used to compute the nonlinear second harmonic (SH) fields in a non-perturbative approach, yielding a theoretical maximum conversion efficiency of 0.5%. Preliminary experimental results will be presented.enTechnology::600: TechnologyConference PaperConference Paper