Author Affiliations
Abstract
1 Institute of Advanced Magnetic Materials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
2 College of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China
3 Department of Materials Science and Engineering, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
Nanogap plasmonic structures with strong coupling between separated components have different responses to orthogonal-polarized light, giving rise to giant optical chirality. Here, we proposed a three-dimensional (3D) nanostructure that consists of two vertically and twistedly aligned nanogaps, showing the hybridized charge distribution within 3D structures. It is discovered that the structure twisted by 60° exhibits plasmonic coupling behavior with/without gap modes for different circular-polarized plane waves, showing giant chiral response of 60% at the wavelength of 1550 nm. By controlling the disk radius and the insulator layer, the circular dichroism signal can be further tuned between 1538 and 1626 nm.
metal-insulator-metal structure nanogaps gap mode twisted stacking charge distribution chiral response Chinese Optics Letters
2021, 19(1): 013601
1 南开大学电子信息与光学工程学院&现代光学研究所, 天津 300071
2 深圳大学纳米光子学研究中心&光电工程学院, 广东 深圳 518060
提出了一种可用于表面增强拉曼测量的基于金属纳米圆盘上方放置金属纳米球颗粒构成的金属纳米结构, 其在径向偏振光束激发下, 由于金属纳米圆盘的呼吸模式表面等离激元共振的作用, 可以形成纵向电场有效增强的间隙模式等离激元共振。 对此进行了有限元模拟计算研究, 计算结果证明该间隙模式的纵向电场分量相对于径向偏振入射光的有效激发横向电场分量增强了100倍以上。 为了更清晰地展现这种新型纳米结构的光谱特性以及表面电场分布特征, 同时对单个金属纳米圆盘, 单个金属纳米球, 金属薄膜, 金属纳米球-金属薄膜这几种纳米结构在同一个模拟计算框架下进行了计算以及比较分析。 由于可以把金属纳米球类比为金属探针的尖端, 所提出的新型间隙模式也有望在针尖型拉曼增强中得到应用。
微纳光学 金属纳米圆盘 表面等离激元共振 间隙模式 Micro-nano optics Metal nanodisc Surface plasmon resonance Gap mode
