Development of manipulation technique of metal nanoparticles for plasmonics

本项目的目的是建立一种利用扫描电子显微镜中的微操作来移动金属纳米颗粒来制造等离子体共振结构的技术。第一年，通过操纵技术证实了利用该技术制造等离子体共振结构的可行性。用石英探针将直径为100 nm的银微球排列成节食器，探针半径为20~30 nm。这些二聚体在长轴偏振时呈现红色散射峰。这些峰被鉴定为在单个球体中激发的偶极散射共振模的反对称键模式。然而，我们遇到了一个严重的问题，即扫描电子显微镜观察对共振性能产生了影响。一方面，我们成功地发现了不需要微操作技术的新型等离子体共振结构，另一方面，我们成功地发现了不需要微操作技术的…S为了获得更多的纳米级间隙，进行了系统的理论计算。因此，在第二年，我们重点建立了新结构的设计方法，并研究了它们的等离子体共振性质。新的发现是，近邻金属纳米粒子中的等离子体激元共振被认为是二维光波在金属包层/介质芯波导中通过开口端的反射传播的法布里-珀罗共振。简而言之，重点是实现有限腔长的金属包层波导，而不是利用微操作技术来实现具有纳米级间隙的粒子的机械排列。在熔融石英衬底上沉积了金/二氧化硅(厚度D=1.756 nm)/金多层膜，并在其边缘用离子束球磨去除周长为3微米、L纳米(L=55-495 nm)的矩形腔谐振腔。正如理论计算所预测的，随着腔长的减小，反射倾角出现蓝移。较少

The aim of this project was to establish a technique to fabricate plasmon resonance structures by moving metallic nanoparticles by use of micromanipulation in a scanning electron microscope.In the first year, the feasibility of plasmon resonance structures by manipulation technique was confirmed. Silver microspheres of 100 nm diameter were arranged into dieters with quartz probes with a tip radius of 20-30 nm. These dimers showed red scattering peaks for long-axis polarization. These peaks were identified as anti-symmetric bonding mode of dipolar scattering resonance modes excited in individual spheres. However, we encountered a serious problem that the resonance properties are affected by the SEM observation. This is caused by the deposition of contamination materials by electron beam irradiation, which forced us to change the original research plan.On the other hand, we succeeded in discovering new types of plasmon resonance structures which do not require micromanipulation technique … More s to obtain nanometric gap, as a result of systematic theoretical calculation. Therefore, in the second year, we focused on establishing the designing method of the new structures, and investigate their plasmon resonance properties. The new findings was that the plasmon resonance in closely neighboring metallic nanoparticles is regarded as the Fabry-Perot resonance of two-dimensional lightwave propagating in metal-clad/dielectric-core waveguides by the reflection at the open ends. In short, the important point is the realization of metal-clad waveguide with a finite cavity length rather than the mechanical arrangement of particles with a nanometric gap by use of micromanipulation technique. Gold/silica(thickness D=1.7-56nm)/gold multilayers were deposited on fused silica substrates, and at their edges rectangular cavity resonators of 3-micrometer width and L-nanometer length (L=55-495nm) were fabricated by removing their circumferential areas by ion beam milling. As has been predicted by theoretical calculation, the blue shifting of reflection dips was observed as the cavity length decreases. Less