Second Harmonic Generation Enhancement from Amorphous Silicon-Gallium Nitride based Guided Mode Resonant Structures

We study second harmonic generation (SHG) enhancement from 5 μm thick Gallium Nitride layer with amorphous silicon sub-wavelength gratings supporting guided-mode resonances. The enhanced SHG is attributed to the excitation of the in-plane nonlinear polarization resulting in efficient SHG collection.