基于微结构金属器件的光束聚焦功能研究摘 要表面等离子体激元本质上是介质-金属界面的电磁倏逝波，表现为金属表面自由电子的集体振荡，P 极化光波照射介质-金属界面能够激发表面等离子体激元，从而突破光学衍射极限，实现纳米聚焦。本文在早先文献的基础上，设计了金属材料、不等间距的矩形狭缝纳米光栅，利用 Comsol Multiphysics 5.0 软件模拟了波长为 632.8nm 的 P 极化光波垂直入射矩形狭缝纳米光栅后的电场，证明了该结构能够实现纳米聚焦。在矩形狭缝纳米光栅能够实现聚焦的基础上，我们首先研究了金属材料对于该结构聚焦效果的影响，定义银、金、铜三种材料分别进行模拟，通过比较光栅对称轴截线上部分焦点的电场强度来比较聚焦效果；其次我们研究了SiO2衬底厚度对于该结构聚焦效果的影响，对SiO2衬底厚度进行参数化扫描，通过比较光栅对称轴截线上一固定位置焦点电场强度来比较聚焦效果；最后，综合以上研究，我们给出了矩形狭缝纳米光栅达到最佳聚焦效果的设计参数最优解。关键字：表面等离子体激元；微结构金属器件；有限元；矩形狭缝光栅；纳米聚焦AbstractSurface plasmons are essentially electromagnetic evanescent waves at the dielectric metal interface, which represent the collective oscillation of free electrons on the metal surface. P-polarized light irradiation on the dielectric metal interface can excite surface plasmons, 1thus breaking through the optical diffraction limit and achieving nanometer focusing. In this paper, based on the previous literature, we design a rectangular slit nano grating with metallic materials and unequal spacing. We use Comsol Multiphysics 5.0 software to simulate the incident of 632.8nm light wave. The electric field of p-polarized light wave perpendicular to the rectangular slit grating proves that the structure can achieve nano focusing. On the basis of focusing effect of rectangle slit nano grating, we first studied the influence of metal materials on the focusing effect of the structure, defined silver, gold and copper materials to simulate respectiv...
