Phase and amplitude sensitivities in surface plasmon resonance bio and chemical sensing
Phase and amplitude sensitivities in surface plasmon resonance bio and chemical sensing
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DOI：
10.1364/oe.17.021191
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发表时间：
2009-11-09
期刊：
影响因子：
3.8
通讯作者：
Grigorenko, Alexander N.
中科院分区：
文献类型：
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作者：
Kabashin, Andrei V.;Patskovsky, Sergiy;Grigorenko, Alexander N.
我们考虑了表面等离子体共振(SPR)条件下反射光的幅度和相位特性，并研究了它们对与生物和化学传感相关的折射率变化的敏感性。我们的分析表明，由于以下原因，相位可以提供至少两个数量级的检测极限：(I)最大的相位变化出现在探测电场矢量最大的SPR曲线的倾角处，而最大幅度变化出现在共振斜率上：这使得相位对折射率变化的敏感度提高一个数量级；(Ii)在适当的检测方案下，相位噪声可以比幅度噪声低一个数量级，从而产生更好的信噪比；(3)阶段为信号平均和滤波以及图像处理提供了更好的可能性。应用相敏SPR偏振测量方案和气体定标模型，实验证明了该方案的探测下限为10(-8)RIU，比幅度敏感方案提高了约两个数量级。最后，我们展示了如何利用相位对图像进行滤波和处理，以提高信噪比，即使在相对噪声较大的检测方案中也是如此。相敏方法结合了更好的物理灵敏度和微阵列成像和传感的可能性，有望对目前可用的SPR技术进行实质性升级。(C)2009年美国光学学会
We consider amplitude and phase characteristics of light reflected under the Surface Plasmon Resonance (SPR) conditions and study their sensitivities to refractive index changes associated with biological and chemical sensing. Our analysis shows that phase can provide at least two orders of magnitude better detection limit due to the following reasons: (i) Maximal phase changes occur in the very dip of the SPR curve where the vector of probing electric field is maximal, whereas maximal amplitude changes are observed on the resonance slopes: this provides a one order of magnitude larger sensitivity of phase to refractive index variations; (ii) Under a proper design of a detection scheme, phase noises can be orders of magnitude lower compared to amplitude ones, which results in a much better signal-to-noise ratio; (iii) Phase offers much better possibilities for signal averaging and filtering, as well as for image treatment. Applying a phase-sensitive SPR polarimetry scheme and using gas calibration model, we experimentally demonstrate the detection limit of 10(-8) RIU, which is about two orders of magnitude better compared to amplitude-sensitive schemes. Finally, we show how phase can be employed for filtering and treatment of images in order to improve signal-to-noise ratio even in relatively noisy detection schemes. Combining a much better physical sensitivity and a possibility of imaging and sensing in micro-arrays, phase-sensitive methodologies promise a substantial upgrade of currently available SPR technology. (C) 2009 Optical Society of America