Narrow groove plasmonic nano-gratings for surface plasmon resonance sensing.
Narrow groove plasmonic nano-gratings for surface plasmon resonance sensing.
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DOI：
10.1364/oe.19.000787
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发表时间：
2011-01-17
期刊：
影响因子：
3.8
通讯作者：
Vo-Dinh T
中科院分区：
文献类型：
--
作者：
Dhawan A;Canva M;Vo-Dinh T
我们提出了一种新的基于窄槽(亚15 nm)等离子体纳米光栅的表面等离子体共振(SPR)结构，使得正常入射的辐射可以耦合到表面等离子体中，而不像在经典的Kretschmann结构中那样使用基于棱镜耦合的全内反射。这消除了基于SPR的传感的角度依赖性要求，并允许开发坚固耐用的小型化SPR传感器。基于严格耦合波分析(RCWA)，数值计算了不同结构的金和银纳米光栅的反射率随SPR纳米光栅周围介质的局域折射率以及入射辐射波长和入射角的变化。我们的计算表明，与传统的基于SPR的传感系统相比，窄槽等离子体光栅中关于折射率局域变化的微分反射信号要高得多。此外，这些计算允许确定最佳纳米光栅几何参数，即纳米线周期、纳米线之间的间距以及纳米光栅中纳米线的高度，以获得对折射率局部变化的最高灵敏度，这是由于生物分子靶结合到功能化的纳米光栅表面而发生的。
We present a novel surface plasmon resonance (SPR) configuration based on narrow groove (sub-15 nm) plasmonic nano-gratings such that normally incident radiation can be coupled into surface plasmons without the use of prism-coupling based total internal reflection, as in the classical Kretschmann configuration. This eliminates the angular dependence requirements of SPR-based sensing and allows development of robust miniaturized SPR sensors. Simulations based on Rigorous Coupled Wave Analysis (RCWA) were carried out to numerically calculate the reflectance - from different gold and silver nano-grating structures - as a function of the localized refractive index of the media around the SPR nano-gratings as well as the incident radiation wavelength and angle of incidence. Our calculations indicate substantially higher differential reflectance signals, on localized change of refractive index in the narrow groove plasmonic gratings, as compared to those obtained from conventional SPR-based sensing systems. Furthermore, these calculations allow determination of the optimal nano-grating geometric parameters - i. e. nanoline periodicity, spacing between the nanolines, as well as the height of the nanolines in the nano-grating - for highest sensitivity to localized change of refractive index, as would occur due to binding of a biomolecule target to a functionalized nano-grating surface.