Collinear second harmonic generations in a nonlinear photonic quasicrystal

LiNbO(3) nonlinear photonic quasicrystal with octagonal symmetry was fabricated. The collinear quasiphase matched second harmonic generations at 22 wavelengths were observed. It is shown that not only the standard type quasiphase matching but also the recently proposed projection-based quasiphase matching plays an important role in these harmonic generations. (c) 2008 American Institute of Physics.