三维六叶风车纳米结构局域表面等离激元共振特性研究  

Properties of Localized Surface Plasmon Resonance in Three-dimensional Six-blade Windmill Nanostructure

作　　者：王兆华[1] 任立庆[1] WANG Zhao-hua;REN Li-qing(College of Energy Engineering, Yulin University, Yulin 719000, China)

机构地区：[1]榆林学院能源工程学院

出　　处：《表面技术》2019年第8期151-155,共5页Surface Technology

基　　金：国家自然科学基金资助项目(51861034);陕西省科学技术厅项目(2014K05-11)~~

摘　　要：目的研究三维六叶风车纳米结构的等离子体特性和光学手性。方法设计了一种可调节三维旋转角度的风车纳米结构。在垂直入射的左圆偏振(LCP)和右圆偏振光(RCP)作用下,通过Comsol多物理场仿真软件,数值分析了不同旋转角度三维风车纳米结构的透射光谱、表面电流分布和磁场强度。为了得到三维风车纳米结构的手性光学特性,计算了其不对称因子。结果在透射光谱中观察到波长为925nm和985nm两种具有不同近场耦合的局域表面等离激元共振(LSPR)模式。当旋转角从0°增加到60°时,内外模式交换各自所在的激发峰位;当旋转角为45°时,三维风车具有较强的光学活性,其不对称因子最大值可达0.6,从而在不同的共振模式下得到了最佳的圆二色性效应。结论LSPR模式对几何参数有很强的依赖性和可调控性,光学手性对风车结构叶片的上升程度具有很强的敏感性。研究结果可为设计新的手性光学纳米结构提供参考,为光电相互作用领域的应用提供新思路。The work aims to study plasmonics characters and optical chirality of three-dimensional (3D) six-blade windmill nanostructure. The 3D windmill nanostructure with adjustable lift-up angle was designed. The transmission, surface current distribution and magnetic field intensity were numerically analyzed by commercial FEM package (Comsol multiphysics) under the normally incident left-(LCP) and right- circularly polarized (RCP) light. To obtain the optical chirality of this 3D windmill nanostructure, asymmetry g-factor was calculated. Two distinct coupling LSPR (Localized Surface Plasmon Resonance) modes with wavelength of 925 nm and 985 nm were observed in the transmission. By increasing lift-up angle from 0° to 60°, internal and external modes exchanged the locations. When lift-up angle was equal to 45°, the 3D windmills showed much stronger optical activity, and the maximum asymmetry g-factor was of 0.6, showing best circular dichroism effect under different resonance modes. LSPR modes have strong dependence and regulation performance on geometrical parameters. The optical chirality is very sensitive to lift-up angle of windmill blade. The results can provide reference for designing novel chiral optical nanostructures, and may provide new ideas in applications of the interactions between photons and electrons.

关 键 词：风车纳米结构 表面等离子体共振 表面增强光谱 手性 圆二色性 

分 类 号：O433.5[机械工程—光学工程]