目前, 利用氧化锌(ZnO)微纳米线结构形成具有自然谐振腔的紫外激光器件引起国内外广泛关注。针对ZnO本征缺陷导致器件发光及稳定性不足等问题, 开展金属局域等离子激元局域场发光增强方面的研究, 对ZnO基紫外激光器件的应用具有十分重要的意义。本文通过理论仿真构建氧化锌微米线结构模型, 对微腔光学损耗及Fabry-Perot(F-P)谐振腔模式演化进行了理论分析。得到ZnO微腔直径变化与F-P谐振模式演化、光学损耗和光强分布的关系。在此基础上通过金属Ag纳米颗粒对ZnO微米线6个表面进行修饰, 发现金属局域表面等离子激元共振耦合效应对微腔周围的损耗光有明显的抑制作用, 并且在金属与微腔的交叉区通过共振耦合效应实现局域场增强。模拟结果表明, 在损耗较大的微腔表面修饰Ag纳米颗粒以后, 光场限域能力提高672%, 而在金属颗粒之间沿X轴方向产生二次耦合现象, 其电场强度更有2倍的增强效果。

At present, the use of zinc oxide(ZnO) micro-nanowire structures in ultraviolet laser devices with natural resonant cavities has attracted wide attention at home and abroad. Aiming at the problems of the luminescence and stability caused by ZnO intrinsic defects, research on the local field luminescence enhancement of plasmons is very important for the application of ZnO-based UV laser devices. In this paper, ZnO micro-wire structure model is constructed by theoretical simulation and the micro-cavity optical loss and Fabry-Perot(F-P) resonant cavity mode evolution are theoretically analyzed. The relationship between the diameter change of ZnO microcavity and the evolution of the F-P resonance mode, optical loss and light intensity distribution is obtained. On this basis, the six surfaces of ZnO microwires are modified by metal Ag nanoparticles. It is found that the resonance coupling effect of metal local surface plasmons significantly inhibited the loss of light around the microcavity and the local field enhancement is realized by the resonance coupling effect at the intersection of the metal and the microcavity. The simulation results show that after the surface of the microcavity is modified with Ag nanoparticles, the confinement ability of the optical field increased by 6.72%, while the secondary coupling occurs along the X axis between the metal particles, and the electric field intensity is enhanced by 2 times.