A simple model for the resonance shift of localized plasmons due to dielectric particle adhesion
A simple model for the resonance shift of localized plasmons due to dielectric particle adhesion
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DOI：
10.1364/oe.20.000524
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发表时间：
2012-01-02
期刊：
影响因子：
3.8
通讯作者：
Kall, Mikael
中科院分区：
文献类型：
--
作者：
Antosiewicz, Tomasz J.;Apell, S. Peter;Kall, Mikael
基于局域表面等离子体共振折射率传感的超灵敏探测器能够检测用于生化分析的非常少量的分子。众所周知，这类传感器的灵敏度主要取决于金属表面周围电磁场的空间分布。然而，局域场增强和共振位移之间的确切联系很少被讨论。使用准静态近似，我们开发了一个模型，该模型将纳米等离子体谐振器的灵敏度与分析物所在的局域场联系起来。该模型得到了有限差分时间域模拟的证实，可以用来估计作为被测物体特性--介电常数和体积--及其在谐振器表面上的位置的函数的位移的大小。它只需要计算金属结构产生的谐振场，因此适合于纳米等离子体传感器的数值优化。(C)2011年美国光学学会
Ultrasensitive detectors based on localized surface plasmon resonance refractive index sensing are capable of detecting very low numbers of molecules for biochemical analysis. It is well known that the sensitivity of such sensors crucially depends on the spatial distribution of the electromagnetic field around the metal surface. However, the precise connection between local field enhancement and resonance shift is seldom discussed. Using a quasistatic approximation, we developed a model that relates the sensitivity of a nanoplasmonic resonator to the local field in which the analyte is placed. The model, corroborated by finite-difference time-domain simulations, may be used to estimate the magnitude of the shift as a function of the properties of the sensed object - permittivity and volume - and its location on the surface of the resonator. It requires only a computation of the resonant field induced by the metal structure and is therefore suitable for numerical optimization of nanoplasmonic sensors. (C) 2011 Optical Society of America