Antosiewicz Tomasz J, Apell S Peter, Claudio Virginia, Käll Mikael
Chalmers University of Technology, Department of Applied Physics, SE-412 96 G¨oteborg, Sweden.
Opt Express. 2012 Jan 2;20(1):524-33. doi: 10.1364/OE.20.000524.
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.
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极少量的分子用于生化分析。众所周知，此类传感器的灵敏度关键取决于金属表面周围电磁场的空间分布。然而，局部场增强与共振偏移之间的确切联系很少被讨论。我们使用准静态近似方法，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放置分析物的局部场联系起来。该模型经时域有限差分模拟验证，可用于根据被感测物体的特性（介电常数和体积）及其在谐振器表面的位置来估计偏移量的大小。它只需要计算金属结构所感应的共振场，因此适用于纳米等离子体传感器的数值优化。
