A nonlinear finite-difference time-domain (FDTD) formalism is developed to model dispersive second-order nonlinear effects in photonic arrangements and optical devices. The dispersion of the second-order nonlinear susceptibility, χ⁽²⁾, is based on the Faust-Henry model, which makes no implicit assumption on the relationship between the linear and nonlinear dispersion. Unlike other models for χ⁽²⁾ dispersion, the Faust-Henry model accurately describes a broad range of crystal classes, including the \( \overline{4}3m \) crystal class, which is essential to generating radiation in the terahertz frequency regime. As such, the developed formalism based on the Faust-Henry dispersion model overcomes limitations imposed by previous FDTD methods for modelling second-order nonlinear effects.

中文翻译：

---

基于浮士德-亨利色散模型的二阶非线性广义时域有限差分形式：在太赫兹生成中的应用

开发了一种非线性有限差分时域（FDTD）形式主义，以对光子布置和光学器件中的色散二阶非线性效应进行建模。二阶非线性磁化率χ ^（2）的色散基于Faust-Henry模型，该模型对线性色散和非线性色散之间的关系没有隐式假设。与其他用于χ ^（2）色散的模型不同，Faust-Henry模型准确地描述了广泛的晶体类别，包括\（\ overline {4} 3m \）晶体级，对于产生太赫兹频率范围的辐射至关重要。这样，基于浮士德-亨利离散模型的发达形式主义克服了以前的FDTD方法对二阶非线性效应进行建模的限制。