Watad Ibrahim, Abdulhalim Ibrahim
Appl Opt. 2017 Sep 20;56(27):7549-7558. doi: 10.1364/AO.56.007549.
There is a debate on whether phase measurement in surface plasmon resonance (SPR) sensors give better resolution than intensity measurement. In this work, we show that each one of the modes can give better resolution depending on the metal layer thickness chosen, as well as the available noise levels in the system. We propose a three point polarimetric approach to extract the ellipsometric parameters and phase information in the spectral mode. It is shown that the polarimetric measurement at its optimal thickness range gives up to seven-fold higher resolution than the intensity, especially at noise levels of off the shelf spectrometers. When noise levels are very low, the resolution in the two modes becomes nearly equal. The same is true when considering the whole SPR curve rather than single point detection. However, it is clearly shown both experimentally and theoretically that the polarimetric measurements at their optimal range give much better resolution than the intensity.
关于表面等离子体共振（SPR）传感器中的相位测量是否比强度测量具有更高的分辨率存在争议。在这项工作中，我们表明，根据所选的金属层厚度以及系统中的可用噪声水平，每种模式都可以提供更高的分辨率。我们提出了一种三点偏振方法来提取光谱模式下的椭偏参数和相位信息。结果表明，在其最佳厚度范围内进行偏振测量时，分辨率比强度测量高出多达七倍，尤其是在现成光谱仪的噪声水平下。当噪声水平非常低时，两种模式下的分辨率几乎相等。考虑整个SPR曲线而不是单点检测时也是如此。然而，实验和理论都清楚地表明，在最佳范围内进行偏振测量比强度测量具有更好的分辨率。
