基于金属纳米结构增强光与物质的相互作用, 调控光学响应是光学前沿研究。金属纳米结构能显著增强电磁场和热点空间位置调控, 是表面等离激元器件应用的关键。借鉴衍射光学元件设计思想, 文中提出一种简单的多尺度叠层圆柱台(double stacked nanocone, DSC)金属纳米结构, 实现近/远场深度调控。在给定激发条件下, DSC纳米结构中腔模与局域表面等离激元模式间产生杂化, 实现多尺度级联场增强, 远场响应也得到有效调制, 且“热点”能有效地定位到纳米结构的上表面。进一步, 提出并研究了掩模重构的纳米加工方法, 低成本、可控地制备了DSC纳米结构, 工艺控制是三台阶DSC器件特性的关键, 实验结果与理论设计一致。

Metallic nanostructures can enhance light-matter interaction arising from the surface plasmonic resonances, which is highlight on optics for many applications. A tunable optical property can be induced by plasmonic resonance, leading to the significant electromagnetic field enhancement, as well as the position of the "hot spot" at a tiny nanogap. Analogue of the diffractive optics, an alternative method of multiscale cascaded field enhancement with a simple metallic nanostructure, double stacked nanocone (DSC), was proposed in the article. In detail, a tunable hybrid mode was achieved from the strong interference between a fundamental plasmonic cavity mode and a plasmonic gap mode. Furthermore, it led to a far-field optical response at a certain wavelength. The position of the hot spots can also be mounted on the top surface of the DSC nanostructure. Additionally, a technique of mask reconfiguration was developed to precisely fabricate the multiscale DSC nanostructure, which can benefit to construct the necessary three steps in the nanostructure. The experimental results also provide a substantial evidence to demonstrate the art-of-state of the multiscale cascaded field enhancement, as well as the technique of nanofabrication.