微介质锥、纳金属锥和纳金属锥孔中的光场调控

The micro-focusing beams generated by micro dielectric cones are presented to illuminate nano metallic cones in this project, in order not only to break the diffraction limit of micro dielectric cones, but also to overcome the problem of the tiny entrance aperture of nano metallic cones. Thus, much more light can be firstly collected by the micro dielectric cones and then efficiently converted to surface plasmon polaritons in the nano metallic cones for achieving final stronger nano-focusing. Theoretical modeling and simulations, micro and nano fabrications, and optical experiments will be performed in detail for micro dielectric cones, nano metallic cones, and nano metallic conic voids. The light momentum and energy transfer will be revealed during the process from micro-focusing to nano-focusing in the combined configuration consisting of micro dielectric cones and nano metallic cones. The excitation and evolution of plasmon polaritons will be further studied to clarify the role that they play in nano-focusing. Three dimensional optical fields tuning, controlling and localized enhancement are expected to be effectively carried out by the joint transforms of the combining configurations of micro dielectric cones and nano metallic cones, their materials and structure parameters. Based on the above achievements, novel atomic force microscope probe will be designed and fabricated by combining micro dielectric cones and nano metallic cones. Nano metallic conic voids will be fabricated and taken as the supporting substrates for the samples of bio-molecules and nano-particles. The novel probe with the combined configuration and nano metallic conic voids will be used together to develop tip enhanced Raman spectroscope with higher spatial resolution and sensitivity. The project will lay solid theoretical and experimental foundations with our own intellectual property rights for developing highly efficient nano-optical antennas, nano-probes and nano-optical circuits, which may have important applications in nano-lithography, nano-sensing, nano-imaging, next generation optical signal processing and sub-wavelength optical communication.

本项目利用微介质锥产生的微聚焦光束照射纳金属锥，既突破了微介质锥的衍射极限，又解决了纳金属锥入口小的局限，尽最大可能地收集入射光能，并有效地转化为表面等离激元，以实现更高的纳米聚焦。通过理论模拟计算、微纳米加工和光学实验，揭示微纳米锥形复合结构中从微聚焦到纳米聚焦过程光动量和能量的转变，深入研究等离激元的激发和演变，明晰其在纳米聚焦中的作用机理。利用微介质锥和纳金属锥结合方式、材料和结构参数等多参量的联合变换，可望实现三维光场的调控和局域增强。在此基础上设计和制作微介质锥和纳金属锥复合的新型原子力显微镜探针，并利用纳金属锥孔作为生物分子和纳米颗粒等样品的基底，构建更高空间分辨和高灵敏的针尖增强拉曼光谱系统。从而为发展具有自主知识产权的高效纳米光学天线、纳米探针和纳米光学回路奠定坚实的理论和实验基础，在纳米光刻、纳米传感、纳米成像以及新一代光学信息处理和亚波长光通信等诸多领域有重要应用价值。

本项目提取纳米光子学、表面等离激元学和近场光学中最具有代表性的微纳米锥、螺旋锥和锥孔中光场的调控进行研究，将微介质锥和纳金属锥形结构的优势结合起来。我们开展了微纳米锥、螺旋锥、非线性锥以及锥孔结构中光场调控的理论分析、模拟计算、微纳米加工和光学实验，揭示了从微介质锥、微介质螺旋锥产生的微聚焦到纳金属锥、纳金属螺旋锥中实现纳米聚焦的过程中动量、能量和力的转化和演变，明晰了等离激元在纳金属锥、纳金属螺旋锥和非线性纳金属锥中的激发和演化规律及其在纳米聚焦中的作用机理。创新性提出了轴对称介质螺旋锥、非对称微介质双螺旋锥、纳米金属螺旋轴锥探针、非线性纳米金属螺旋锥、e指数型非线性纳米金属锥、微介质锥和纳金属光栅复合的光学探针、微介质螺旋锥和金属粮仓形纳米锥复合探针等多种微纳米光学探针，实现了微纳米聚焦矢量光场强度、位相、偏振等光学特性的同时调控，其中：e指数型非线性纳米金属锥探针产生的纳米聚焦，其电场的最大强度为188230 a.u.，其纵向分量为95125 a.u.；非线性纳米金属螺旋锥使强度增加了四个数量级，纵向电场强度占总电场强度的54.5%以上，偏振方向改变值在35%以上。研究了微介质锥和纳金属锥新型探针的制备技术和工艺，利用激光直写和电感耦合等离子体刻蚀技术制备了微介质锥，利用电化学腐蚀技术制备了非线性纳金属锥，初步构建了高空间分辨率和高灵敏度的针尖增强拉曼光谱检测实验系统。此外，我们还利用电化学阳极氧化法制备了部分周期纳米孔,研究了纳米孔中心位置和半径大小随机变化其反射光谱作用机理；提出并利用五次方位相结构产生的曲面光束在纳米银膜表面激发了曲面表面等离激元。从而为发展具有自主知识产权的高效的纳米光学天线、纳米探针和纳米光学回路奠定了坚实的理论和技术基础，在纳米光刻、纳米传感、纳米成像以及新一代光学信息处理和亚波长光通信等诸多领域有重要应用价值。