光学超构材料的人工二阶非线性效应理论研究

Second-order nonlinearity of optical metamaterial simultaneously possesses the advantages of metamaterials and second-order nonlinearity, and has great potentials in application of optical communication, optical calculation and generating new light source. Here, we proposed a series of solution to solve the restrictions of this area, such as lacking of an analytical theory model and focusing on second-harmonic generation. The research contents include: extending the discrete dipole model to second-order nonliearity and deriving a second-order nonlinear coupled-dipole model, analytically unveiling the physical mechanism of artificial second-order nonlinearity; according to the effective polarizability of second-order nonlinearity and nonlinear Rayleigh-Wood relation building metamaterial to obtain sum- and difference-frequency generation; with the help of theory and electromagnetic simulation, investigating the influence of bumping and signal light on second-order nonlinearity; investigating the influence of plasmonic electromagnetic resonance on the second-order nonlinearity and by using the metamaterial to generate ultraviolet and THz light sources; theoretically studying the activity of artificial second-order nonlinearity via introduction of electro- and thermo-optical material. The research findings lay certain theory foundations of nonlinearity based on optical metamaterial and improving the potential in application.

光学超构材料的二阶非线性效应同时具有超构材料和二阶非线性的优势，在光通信、光计算、产生新光源等领域具有巨大应用前景。本项目针对超构材料的二阶非线性研究缺少一种简单易行的通用解析理论模型，且研究成果大多集中于二次谐波的增强与调控的问题，提出一套解决方案。推导基于离散偶极子模型的二阶非线性偶极子耦合模型，解析地研究人工二阶非线性的物理机制；根据等效二阶非线性极化率表达式的一般形式，结合非线性瑞利-伍德条件，相应地设计超构材料产生和频、差频等二阶非线性效应；采用理论与电磁仿真结合的手段，阐明泵浦光、信号光、等离激元电磁共振模式对二阶非线性影响，并针对特定波长优化设计超构材料生成紫外和太赫兹波段的光源；最后通过引入电调控、热调控的线性介质，结合理论模型探讨人工二阶非线性的动态可调性。项目成果将为光学超构材料的非线性效应的理论研究及其应用前景打下坚实的基础。

光学超构材料的二阶非线性效应同时具有超构材料和二阶非线性的优势，在光通信、光计算、产生新光源等领域具有巨大应用前景。本项目针对超构材料的二阶非线性研究存在的问题，开展相关研究。项目主要围绕光学超构材料的人工二阶非线性效应的产生、增强和调控展开。借助超构材料的磁场共振、环形偶极子共振、法诺共振等，将电磁场更好地局域在结构近场范围，增强了非线性效应，通过引入相变材料、石墨烯等方案，对非线性信号进行调控；针对电磁耦合超构材料，提出近场耦合激发、双共振匹配等方法，增强了基于磁场洛伦兹力的非线性效应；结合拓扑光子学，研究了拓扑光子晶体中边界态、角态增强、调控非线性信号，提出利用克尔效应打破空间反演对称性，构造与重构光子晶体拓扑特性。这些结果加深对纳米尺度非线性光学效应物理内涵的理解，对于非线性光学在光信息传输、处理领域的应用具有重要意义。申请人以第一或通信作者身份已发表论文13篇，申请发明专利多项，另有多篇论文处于待发表状态。