基于金属腔中表面等离子激元共振效应的纳米孔阵列加工基础研究

High-energy laser beams are widely used in high quality micro/nano-holes precision manufacturing. For the laser processing of a large number of micro/nano-holes, one way is to drill holes one by one with a laser beam and another way is to drill many holes simultaneously with multiple laser beams. However, the first way is very time-consuming and low efficiency, and the second way makes the laser control system become very complex. Here, we propose a new processing method to solve the above problems. A metallic microcavity is fabricated on the surface of the workpiece and irradiated by a short pulse laser, then surface plasmon polaritons (SPPs) are excited in the cavity. The SPPs oscillate back and forth in the metallic cavity, forming an array of nanoscale energy beams. Since these nanoscale beams with high energy can ablate the workpiece, a nanohole array is obtained, which greatly increases the efficiency of laser drilling. The dimensions of the metallic cavity can be designed by numerical simulation. The relationship between the laser parameters and the SPPs intensity in the cavity can be obtained by numerical simulation. The dependence of the SPPs intensity on the cavity size can be received by numerical simulation. By simulating and analyzing the ablation process of the nanohole array, the material removal mechanism can be revealed, and the dependence of hole diameter and hole depth on the incident laser energy can be obtained. The influence of the cavity dimensions and laser parameters on the morphology and size of the nanohole array was studied, and the controllable manufacturing method of the nanohole array was discussed.

高能量的激光束广泛应用于高质量微/纳米孔的精密制造，针对激光逐点打孔耗时长、效率低，而多束激光同时打孔控制复杂的问题，本项目提出通过在工件上制备微米尺度的金属腔，并利用一束短脉冲激光照射在金属腔中产生表面等离子激元，表面等离子激元在金属腔中来回振荡形成阵列排布的纳米尺度的能量束，然后利用阵列排布的纳米尺度的能量束烧蚀工件，获得纳米孔阵列，目的是为了提高激光制孔的效率。借助数值仿真技术设计金属腔，建立激光参数、金属腔的尺寸与表面等离子激元强度的关联。对纳米孔的加工过程进行仿真分析，揭示金属腔中的表面等离子激元能量束烧蚀工件获得纳米孔的去除机理，得到纳米孔的孔径、孔深随入射激光能量的变化关系。研究金属腔的几何尺寸、激光参数对纳米孔阵列的形貌、尺寸的影响，探讨纳米孔阵列的可控制造方法。

纳米孔阵列在太阳能电池、发光器件、生物检测和传感器等领域具有重要的应用。激光精密加工是一种制造纳米孔阵列的重要方法。针对单束激光逐点加工纳米孔存在耗时长、效率低、形貌差等问题，本项目提出金膜和微球协同辅助激光加工纳米孔阵列的方法，即通过在衬底表面镀金膜来改善激光直接加工纳米孔的形貌，并在金膜表面铺设单层致密排列的微球来提高激光加工纳米孔的效率。项目主要研究工作包括：研究铺球参数对微球排列的影响，获取在衬底表面铺设大面积致密排列的单层微球的最优参数；研究微球的直径、激光参数对纳米孔阵列的形貌和尺寸的影响规律，建立纳米孔阵列尺寸与微球直径、激光参数的映射规律；研究激光、微球、金膜、衬底之间的能量传递过程，揭示微球和金膜协同辅助激光高效高质加工纳米孔的机理；仿真模拟硅、蓝宝石衬底表面纳米孔阵列的尺寸对太阳光吸收率和发光二极管的出光效率的影响规律，获得硅、蓝宝石衬底表面纳米孔阵列的最优尺寸。在此研究基础上，实现了在硅衬底上快速制作直径约550nm、深度约100nm的纳米孔阵列，且纳米孔周围几乎无溅射物、孔内非常光滑。利用该技术单次可获得几千个纳米孔，其加工效率远远高于传统激光逐点打孔。项目研究成果将为纳米孔阵列的高效精密加工提供理论基础和技术支撑。在本项目的资助下，已在国内外著名期刊上发表高质量研究论文12篇（其中SCI论文10篇，EI论文2篇），申请中国发明专利2项，授权实用新型专利2项，培养硕士生3名。