基于牛眼类金属微纳结构的光学偏振调控

Photonic integration is a major direction of development in the current field of optics. Radially polarized light has a wide range of applications in many varied areas with its unique optical properties, and it has very important significance to achieve the preparation of radially polarization light in micro- and nanoscale. Photons can be transmitted and controlled in subwavelength scale by surface plasmon on metal nanostructure, and this raised a method for the realization of photonic integrated circuit. The bull's eye nanostructure can only excite radial surface plasmon because of its unique structure features, so it has a natural advantage in the preparation of the radially polarized light. The project will make an in-depth research based on preliminary work, using multiple methods including theoretical analysis, numerical simulation and experiment to analyze the polarization properties of bull's eye nanostructure, search for the structue model and parameters which have excellent polarization controlling performance and develop optical elements which can prepare the radially polarized light in convenience and efficiency in the nanoscale，and explore its application in optical tweezers, lithography and optical imaging etc.

光子集成是当前光学发展的一大趋势。径向偏振光以其独特的光学特性，在许多领域都有着广泛的应用，实现微纳尺度下对径向偏振光的制备，具有十分重要的意义。利用金属微纳结构中的表面等离激元，可以在亚波长尺度来传输和调控光子，为实现光子集成提供了一条可能的途径。牛眼类金属微纳结构因其结构特征，只能激发沿径向振动的表面等离激元，在制备径向偏振光时具有天然的优势。本项目将结合前期已有的工作基础，结合理论推导、数值模拟、实验测量等多种途径深入开展研究：分析牛眼类结构的偏振特性，寻找具有优质偏振调控特性的结构模型和结构参数，研发能够在微纳尺度简便高效制备径向偏振光的微纳光学元件，并进探索其在光镊、光刻以及光学成像等方面的应用。

本项目执行期间的主要工作有：. 不同偏振光在金属螺旋缝隙结构中的光学特性分析。我们将径向偏振光和线偏振光分别作用在纳米螺旋结构中，观察到了不同偏振光和不同结构螺旋度对透射光性质的影响。. 银纳米线-量子点耦合系统的光学偏振特性研究。我们将线偏激发光作用于银纳米线-量子点耦合体系时，耦合体系中量子点荧光的偏振特性会受到激发光方向的调制。. 表面等离激元在金属纳米台阶中的传输机制分析。我们模拟分析了金属纳米台阶结构中表面等离激元的能量传输特性，发现共有三个物理机制参与了传输过程：光学震荡的耦合、电子震荡的耦合、台阶纵向界面的法布里-珀罗腔耦合。