金属等离激元经典与量子效应以及线性和非线性增强受到广泛关注。本项目拟对经典和量子等离激元体系两个二阶非线性效应进行研究: 量子体系二阶等离激元激发(Double Plasmon Excitation, DPE)和经典体系等离激元对二次谐波(SHG)的增强。两者分别受制于小量子体系的弱散射和中心对称体系禁戒偶极跃迁。因此，我们提出利用经典与量子等离激元的耦合增强DPE和等离激元磁共振模式Fano效应增强SHG发射。我们将对比研究量子尺寸纳米颗粒等离激元的量子极限和DPE；研究非对称金属纳米结构中等离激元多极振荡和磁共振模式Fano效应增强SHG；利用复合金属纳米结构中局域场和DPE共振能量转移增强SHG。本项目涉及到等离激元的磁共振模式、量子效应和非线性增强三个热点研究方向，有助于揭示等离激元的量子特性并提高其激发能量共振转移，对制备基于等离激元的二阶非线性纳光子器件具有非常重要的应用价值。

Classical and quantum effects of plasmon resonance as well as linear and nonlinear enhancements in metal nanostructures have attracted considerable attention recent years. In this proposal, we investigate two second order nonlinear effects of classical and quantum plasmonic systems: double plasmon excitation (DPE) of quantum systems and second harmonistic generation (SHG) enhancement from classical systems. Two nonlinear effects are limited by the weak scattering cross section and the dipole forbidden in the centrosymmetric materials, respectively. Therefore, we propose the project to enhance DPE efficiency by the coupling of classical and quantum systems and improve SHG via plasmonic Fano resonance. We will study: 1) critical sizes of gold and silver quantum plasmon and DPE, 2) the multipole resonance and magnetic modes of asymmetric metal nanostructures, 3) SHG enhancement by plasmon-enhanced local field and resonance energy transfer from the PDE. This project involves three hot topics in nanooptics: magnetic plasmon modes, quantum plasmon, and nonlinear enhancements. This study will be helpful to uncover the quantum behaviours of plasmon resonance, to improve the resonance energy transfer efficiency, and have great significance to design and fabricate the second order nonlinear micro/nano photonic devices.