一维布洛赫表面波的生成及其应用基础研究

Although the Bloch Surface Wave (BSW) loaded by dielectric multilayer was proposed by A. Yariv in 1977, extensive studies and applications of BSW only recently began receiving attention within a few research groups, 20 years after BSWs were first examined at the end of the 1970s, mostly due to the rapid development of Plasmoics. Similar as the Surface Plasmon Polaritons (SPP), BSW also has the properties of surface localization, sensitivity to the environment, and suppressing the wavelength. They both can be seen as the medium of two dimensional (2D) optics. Known to all, in Plasmonics, silver nanowire can sustain transform the 2D SPP into the 1D SPP, where the SPP only propagating along the 1D nanowire, but not spread onto other 2D surface, the 1D SPP is more suitable for applications, such as optical circuits for signal transportation, signal processing and so on. The 1D SPP is one of the hot topics in Nanophotonics. But till now, there are no reports on how to realize or propose the 1D BSW. BSW can be considered as the dielectric analogue of SPP with less loss, and the dielectric structures for BSW is also more stable than the metal structures for SPP, and easier to be integrated with silicon based optical devices. In this proposal, polymeric nanofiber made with electron spinning method will be introduced on to the dielectric multilayer of optimized parameters, and then create the 1D BSW, where the BSW only propagates along the 1D nanofiber but not spread on the dielectric surface. This configuration will be sensitive to the surrounding medium, which will be used to develop novel nanofiber based optical sensor. Our findings will be helpful for deeply understanding of the optical surface waves, and provide new thoughts and potentials for Nanophotonics.

虽然介质多层膜负载的布洛赫表面波（BSW）1977年就被A. Yariv提出，但其重新引起关注得益于快速发展的表面等离激元学。类似于表面等离子体波（SPW），BSW也具有表面局域、环境敏感、短波等特性。BSW可看作介质版SPW，但其损耗远小于SPW；相较于金属，介质薄膜稳定性更好；介质结构易于与硅基光子器件结合。众所周知，一维（1D）金属纳米结构，如银纳米线可用于实现1DSPW，更适用于光子回路中信号的传输、处理，是纳米光子学研究热点之一。但至今却鲜见1DBSW的报道。本项目中，申请人拟将静电纺丝技术制备的纳米线引入到介质多层膜中，优化结构参数，将多层膜上2DBSW转换为纳米线中1DBSW。利用纺丝技术的可纺物质种类繁多、工艺可控等优点，实现长传输距离1DBSW光波导；通过调节1DBSW光场分布，使其对外界变化更加灵敏，发展新型纳米光波导传感器件。

存在于全介质多层膜（折射率不同的薄膜交替叠加组成）表面的布洛赫表面波Bloch Surface Waves, BSWs），可以看作是介质版surface plasmons (SPs)，也是一种二维局域表面态，具有场增强、环境敏感与短波效应。同样能够实现类似于SPs的传感、场增强等各种功能。相较于SPs，BSWs的优势是传输损耗小，可以存在于TM或者TE偏振状态；介质结构稳定性优于金属结构，对发光粒子没有淬灭效应。本项目中，负责人主要研究光学薄膜结构布洛赫表面波的生成、调控及其应用。在光学薄膜应用于显微成像方面：将负载有布洛赫表面波的介质多层膜与旋转照明模块引入到光学显微成像系统，实现了一种新型的高灵敏度、高分辨率表面成像与传感系统；通过调控光学薄膜的光子带隙结构及其在不同角度的透过率函数，研制出一种基于光学薄膜的显微成像照明元件，将其作为样品基片，可在常规光学显微镜上实现高对比度的暗场显微成像与全内反射照明显微成像，为发展多功能、低成本、高稳定性的光学显微成像系统提供了新思路。技术应用方面，将自主研制的表面成像与传感系统引入到单个超细大气颗粒物吸湿增长过程的原位增长监测；实现了百纳米尺寸以下单个纳米颗粒的高精度粒径筛分；为大气环境污染溯源和追因研究提供了科学研究工具。光学薄膜应用于片上光学元件方面：借助光学薄膜的带隙结构特性，降低了金属纳米线传输损耗；利用布洛赫表面波的多偏振特性，在光学薄膜上实现了多种片上光学元件，如片上反射镜、分束镜、偏振依赖光开关等，为发展片上光学实验室提供了基本光学元件。水环境中光学表面波方面：借助于光照下，光学薄膜内部或表面产生的光热、光力效应，实现了单个微米粒子的大范围操控、大量微米粒子或细胞的聚集和迁移，为调控生化反应速度、生物膜的形成、群体感应、细胞或微粒的定点操控等提供了新方法。受项目资助，以第一或通讯作者发表SCI论文18篇，申请发明/实用新型专利6项。毕业博士生3名。积极参加国内外学术交流，在学术会议做邀请报告5次。