Research on Second Harmonic Generation in Two-Dimensional Periodical Nonlinear Photonic Crystals Based on Intelligent Materials

The works are focused on finding out proper shape of reversed domains to obtain effective harmonic generations with high conversion efficiency. The conversion efficiency of second harmonic wave in two-dimensional nonlinear photonic crystals consisting of square lattice and reversed domains of various shapes are studied numerically. The shapes of reversed domains are extended from circle, square to ellipse and rectangle. The conversion efficiency of different order quasi-phase matched process can be maximized by adjusting the orientation of noncircular reversed domains. Moreover, a cross-shaped reversed domain is utilized to improve the conversion efficiency of two-order non-collinear quasiphase matching.