二维非线性光子晶体中的高阶准相位匹配谐频

High-order quasi-phase matching harmonic generation in two-dimensional nonlinear photonic crystal

在二维正方晶格的周期性极化铌酸锂晶体中,通过调节基频光波长实现了皮秒光束的高阶共线及非共线准相位匹配谐频过程,在垂直于入射光束的方向上观察到了多对红、绿、蓝三种颜色的谐频光斑.同时,通过改变晶体的入射角度也实现了基频光的高阶谐频过程.实验与理论符合得很好,这一结果对光电子集成及紧凑器件的研究发展有重要的指导意义.

The high-order collinear and non-collinear quasi-phase matching harmonic generations were realized in a two-dimensional periodically poled LiNbO3 with square lattice by tuning the input wavelength. The output spots lay at different symmetric positions with respect to the input beam of picosecond pulse, and the relative intensities of spots at certain wavelengths were measured. The high-order nonlinear harmonic processes were also realized by tuning the input angle. The experimental and theoretical results are in good agreement with each other. Our studies might be beneficial to the development of optics integration and compact devices.