深亚波长金属狭缝间模式干涉及亚衍射聚焦

Fano resonance and near-field interference cause a number of new physical phenomena, and provide new approaches and methods for manipulating light at nanoscale. This is an attractive foreland field in nanophotonics. Based on our previous work, in this proposed project we will focus on the mechanism and manipulation of modal interference among deep subwavelength slits in a metal and the corresponding new optical phenomena. Specifically, we will investigate the following subjects: (1) based on mode matching method, analytically reveal the generation mechanism of Fano resonance in nonperiodic multiple-slits and establish the theoretical model; (2) by means of theoretical analysis and numerical simulation, fully investigate the influence of every factors and geometrical parameters on the lineshape of Fano resonance and distribution of electromagnetic field, then elucidate manipulating method of modal interference in a kind of system like multiple-slits, also offer an approach of manipulating amplitude and phase at subwavelength; (3) investigate deep-subdiffraction-limit superfocusing enabled by a Fano resonance, by optimal design, to achieve the performance better than ordinary schemes of subdiffraction limit focusing; (4) explore the transform of the two dimensional results to three dimensional annular structure, superscattering and other new phenomena. This project will enable us to master theoretical model and manipulation methods of modal interference among multiple slits, as well as related physical phenomena, and expand our understanding on the fundamental problem of interaction of light with nanostructure. The research in this proposal not only possesses great scientific significance, but also will find valuable applications in untrasensitive biochemical sensing, nanolithography and nano-resolution optical imaging, nano-optoelectronic devices and quantum optical communications.

Fano谐振和近场干涉产生了一些新颖物理现象，为纳米光场调控提供新的思路和方法，是引人关注的前沿领域。本项目拟围绕深亚波长金属狭缝间模式干涉机制、调控方法及相应新颖光学现象展开。重点研究：基于模式匹配方法，解析地揭示非周期多狭缝中Fano谐振的产生机制，建立理论模型；通过理论分析和数值模拟方法，研究各个要素、参数对Fano线型和电磁场分布的影响，阐明该类系统的调控方法，提供一种在亚波长尺寸上相位和幅度操控方法；研究基于Fano谐振近场干涉的深亚衍射极限聚焦，进行优化设计，取得优于常见亚衍射极限聚焦方法的性能；探索二维研究成果向三维同心圆结构延伸、超散射和其它新颖现象。本项目的实施将使我们掌握多狭缝模式干涉的理论模型与调控方法以及相关现象的物理原理,拓展对光与纳米结构相互作用这一基础课题的理解，具有重要科学意义，在高灵敏度生化传感、纳米光刻与成像、纳米光电器件和光量子通信中具有很高应用价值。

针对金属膜上非周期紧密排列的多条深亚波长狭缝，本项目紧紧围绕其与光的相互作用展开近场模式干涉相关问题的研究。实施过程中，首先采用模式匹配方法分析狭缝腔之间的近场耦合机理，建立理论模型，然后对模式干涉导致的Fano谐振，进行了较为系统的研究，考察狭缝结构参数和折射率分布对Fano谐振的影响，探索Fano谐振的调控机理与方法，最后对模式干涉产生的亚衍射聚焦现象进行性能分析和优化设计。本项目完成了既定研究目标和内容，主要成果包括：（1）确定了单狭缝和小孔的电磁场模式和调控方法；（2）建立了非周期多狭缝中近场干涉的基本理论；（3）揭示了狭缝结构Fano谐振的产生机理；（4）找到了结构参数作用于狭缝Fano谐振特性的一般规律；（5）对REI亚衍射极限聚焦进行了优化设计。本项目的成功实施使我们掌握了金属膜多狭缝模式干涉的理论模型与调控方法，丰富了光与平面纳米结构相互作用的研究，能为纳米光子学的应用研究提供有价值的参考。