Wang Daqian, Yu Xinglong, Yu Qiuming
Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
Nanotechnology. 2012 Oct 12;23(40):405201. doi: 10.1088/0957-4484/23/40/405201. Epub 2012 Sep 14.
We propose and demonstrate strongly enhancing electric field and Raman scattering with a large tolerance to the light incident angle and polarization by using x-shaped quasi-3D plasmonic nanostructure arrays (X-Q3D-PNAs). The finite-difference time-domain simulations were used to study the reflectance spectra and electric field profiles of X-Q3D-PNAs. Results show that both surface plasmon polaritons and localized surface plasmon polaritons (LSPPs) can be generated at the metal/dielectric interfaces of the top gold thin film with square grating x-shaped nanoholes. The resonance of the LSPPs generated at the gold islands formed between x-shaped nanoholes at the top gold thin film greatly enhance the electric fields at the tips of the cross-sectors of the x-shaped nanoholes. Both plasmon resonances and electric field enhancements are affected by the structural dimensions. The strong electric field enhancement and the large tolerance to the laser polarization were demonstrated by surface-enhanced Raman scattering experiments. This unique plasmonic property of X-Q3D-PNAs could be attractive for photovoltaics and biosensing applications.
我们提出并证明，通过使用x形准三维等离子体纳米结构阵列（X-Q3D-PNAs），可以在对光入射角和偏振具有大容差的情况下强烈增强电场和拉曼散射。使用时域有限差分模拟来研究X-Q3D-PNAs的反射光谱和电场分布。结果表明，表面等离子体激元极化激元和局域表面等离子体激元极化激元（LSPPs）都可以在具有方形光栅x形纳米孔的顶部金薄膜的金属/介电界面处产生。在顶部金薄膜的x形纳米孔之间形成的金岛处产生的LSPPs的共振极大地增强了x形纳米孔交叉部分尖端处的电场。等离子体共振和电场增强都受结构尺寸的影响。表面增强拉曼散射实验证明了强电场增强和对激光偏振的大容差。X-Q3D-PNAs的这种独特的等离子体特性对于光伏和生物传感应用可能具有吸引力。
