Ultraviolet surface-emitted second-harmonic generation in GaN one-dimensional photonic crystal slabs

We report on the observation of an exalted second-harmonic generation process related to a resonant effect inside a GaN photonic crystal slab. The measured enhancement factor, close to ${10}^4$, is the highest measured in this photonic crystal slab resonant configuration. This frequency conversion process is also successfully compared to a rigorous modeling using a scattering matrix formalism. In addition, an original polarization study is proposed, leading to an evaluation of the relative contributions of the fundamental and the second-harmonic modes resonances in the second-harmonic response magnitude.