Hutchison James A, Centeno Silvia P, Odaka Hideho, Fukumura Hiroshi, Hofkens Johan, Uji-I Hiroshi
Division of Molecular and Nano Materials, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee 3001, Belgium.
Nano Lett. 2009 Mar;9(3):995-1001. doi: 10.1021/nl8030696.
We demonstrate that focused laser excitation at the end of silver nanowires of 50-150 nm diameter excites SERS hot-spots at points of nanoparticle adsorption many micrometers along the wire due to the plasmon waveguide effect. The total SERS intensity detected at the hot-spots following wire-end excitation correlates with the known wavelength, polarization, and distance dependences of surface plasmon polariton (SPP) propagation in nanowires. The SERS spectra obtained at the hot-spots following wire-end excitation show very little background compared to when excitation occurs directly at the hot-spot, suggesting that a much smaller SERS excitation volume is achieved by remote, waveguide excitation. The ability to transfer SERS excitation over several micrometers, through a structure with a subdiffraction limit diameter, is discussed with respect to potential high-resolution SERS imaging applications.
我们证明，由于等离子体波导效应，在直径为50 - 150 nm的银纳米线末端进行聚焦激光激发，会在沿纳米线数微米处的纳米颗粒吸附点激发表面增强拉曼散射（SERS）热点。在纳米线末端激发后在热点处检测到的总SERS强度与表面等离激元极化激元（SPP）在纳米线中传播的已知波长、偏振和距离依赖性相关。与直接在热点处激发相比，在纳米线末端激发后在热点处获得的SERS光谱显示出非常低的背景，这表明通过远程波导激发实现了小得多的SERS激发体积。针对潜在的高分辨率SERS成像应用，讨论了通过具有亚衍射极限直径的结构在几微米范围内转移SERS激发的能力。
