金属微纳结构材料的非线性光学效应研究

Recently there has been an extensive worldwide effort to study the metallic microstructures and their corresponding novel optical effects, which has received tremendous attention in the research of physics, material science, information science, life science as well as their interdisciplinary. Therefore, the research for fundamental physics and the potential application shows a special importance. Combined with the characteristics of our group research, in this project, we study the fundamental characteristics of the localized electric and magnetic plasmon modes excited in the metallic microstructures. It is demonstrated that the localized plasmon modes could be coupled with each other to generate some novel optical effects. Accompanied with the interaction between plasmon modes, the intensities of the localized electric and magnetic fields are found to be greatly enhanced, which may open a new way to enhance the localized fields. Further tunability on the localized plasmon modes and their coupling effects could be gained either by tuning the morphology of the constitutes of the metallic microstructures, or by controlling the periods of the metallic microstructures. In particular, the nonlinear optical properties of the metallic microstructures themselves and the combination of the nonlinear materials and metallic microstructures are detailedly investigated under the enhanced localized electric and magnetic fields conditions. A micro theoretical model is established for the relevant enhanced nonlinear optical effects. A thorough investigation is preformed in the effect of the structural symmetry and lattice symmetry of the metallic microstructures on both the second-order harmonic generation and third-order harmonic generation. We also study the potential applications of the present metallic microstructures on the Surface Enhanced Raman Scattering (SERS). We develop the fabrication techniques of metallic microstructures and the accurate control methods of the structural parameters such as morphology, symmetry and period.

有关金属微纳结构材料及其光学新效应的研究是当今物理、材料、信息和生命科学及交叉领域的热点课题之一，因此对其基础问题的研究和潜在应用的探索有着非常重要的意义。本项目结合课题组的研究特色，研究金属微纳结构中的局域电、磁SP共振模式的激发特性，研究这些模式通过近场耦合、远场衍射耦合所带来的新效应，分析通过模式耦合进一步提高局域电场和局域磁场的强度，发展微纳结构中局域电磁场增强的新原理、新方法；利用单个结构单元的构型变化以及周期调制实现对金属微纳结构及其有序阵列中的电、磁SP共振模式和耦合效应的调谐；研究局域电场和局域磁场增强条件下的非线性光学特性，及相关非线性增强的微观理论模型；考察单元结构对称性以及点阵结构对称性对二次谐波、三次谐波产生的影响；研究这类金属微纳结构在表面增强拉曼散射方面的应用；结合材料的优化设计，发展具有SP共振、具有远近场耦合效应的金属纳米结构的制备及其精确调控的实验技术。

金属微纳结构材料及其光学新效应的研究是当今物理、材料、信息和生命科学及交叉领域的热点课题之一。项目四年中在金属微纳结构材料的制备和结构参数精确调控，表面等离激元的激发、传播、耦合与辐射调控的新原理、新方法，基于等离激元激发的局域电磁场增强效应研究，等离激元激发下的线性和非线性光学新效应研究，以及基于金属微纳结构的等离激元传感和增强的光电转换效应等方面进行了深入的研究和讨论，获得了一系列具有自主知识产权的研究成果，在重要学术期刊上发表论文10余篇，同时，在金属微纳结构增强红外光电转换方面以及高效SERS衬底方面申请国家发明专利2项。我们相信本项目的研究成果及课题组以此为积累的后续工作，对当前纳光子学基础问题的研究和潜在应用的探索有着非常重要的意义。