From Ewald sphere to Ewald shell in nonlinear optics.
From Ewald sphere to Ewald shell in nonlinear optics.
复制标题
DOI：
10.1038/srep29365
复制
发表时间：
2016-07-08
影响因子：
4.6
通讯作者：
Zhu YY
中科院分区：
文献类型：
--
作者：
Huang H;Huang CP;Zhang C;Hong XH;Zhang XJ;Qin YQ;Zhu YY
埃瓦尔德球是描述晶体中X射线布喇格衍射的一种简单矢量格式。一个类似的方法，称为非线性埃瓦尔德球，被用来说明光学频率转换过程。我们将非线性Ewald球推广到Ewald壳结构。利用Ewald壳，各种准相位匹配（QPM）效应，诸如与多个QPM共振相关联的集体包络效应、由于多个倒易矢量而增强的二次谐波产生等，理论上提出并得到实验验证。通过旋转非线性光子晶体样品，观察到了这些准相位调制效应的动态演化，与Ewald壳层模型吻合较好。
Ewald sphere is a simple vector scheme to depict the X-ray Bragg diffraction in a crystal. A similar method, known as the nonlinear Ewald sphere, was employed to illustrate optical frequency conversion processes. We extend the nonlinear Ewald sphere to the Ewald shell construction. With the Ewald shell, a variety of quasi-phase-matching (QPM) effects, such as the collective envelope effect associated with multiple QPM resonances, the enhanced second- harmonic generation due to multiple reciprocal vectors etc., are suggested theoretically and verified experimentally. By rotating the nonlinear photonic crystal sample, the dynamic evolution of these QPM effects has also been observed, which agreed well with the Ewald shell model.