Development of manipulation technique of metal nanoparticles for plasmonics

本研究课题的目的是建立在扫描电子显微镜中，通过微操作移动金属纳米粒子，制造等离子体共振结构的技术。第一年，确认了通过操作技术制造等离子体共振结构的可行性。将直径为100 nm的银微球排列成具有尖端半径为20-30 nm的石英探针的dieter。这些二聚体显示出长轴偏振的红色散射峰。这些峰被确定为在单个球体中激发的偶极散射共振模式的反对称键合模式。然而，我们遇到了一个严重的问题，共振性能的影响，由SEM观察。这一方面是由于电子束辐照导致污染物质沉积，迫使我们改变了原来的研究计划。另一方面，我们成功地发现了不需要微操纵技术的新型等离子体共振结构 关于我们 通过系统的理论计算，得到了纳米间隙。因此，在第二年，我们专注于建立新结构的设计方法，并研究它们的等离子体共振特性。新的发现是，在紧密相邻的金属纳米粒子的等离子体共振被视为法布里-珀罗共振的二维光波在金属包层/介质芯波导中传播的开口端的反射。简而言之，重要的是实现具有有限腔长的金属包层波导，而不是通过使用微操作技术将具有纳米间隙的颗粒机械排列。在熔融石英衬底上沉积金/二氧化硅（厚度D=1.7- 56 nm）/金多层膜，通过离子束铣削去除其周边区域，在其边缘制备了宽3 μ m、长L-纳米（L=55- 495 nm）的矩形腔谐振器。正如理论计算所预测的那样，随着腔长的减小，观察到反射下降的蓝移。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