Diffraction-based tracking of surface plasmon resonance enhanced transmission through a gold-coated grating.
Diffraction-based tracking of surface plasmon resonance enhanced transmission through a gold-coated grating.
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DOI：
10.1021/ac201096f
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发表时间：
2011-06
影响因子：
7.4
通讯作者：
Wei-Hsun Yeh;Joseph W. Petefish;A. Hillier
中科院分区：
文献类型：
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作者：
Wei-Hsun Yeh;Joseph W. Petefish;A. Hillier
表面等离子体共振增强透过金属涂层纳米结构是定量测量表面过程的一种高度灵敏而简单的方法，在薄膜和吸附传感器的开发中特别有用。衍射诱导的表面等离子体激元激发可以在可见光光谱的特定区域产生增强的透射率，与这些透射峰相关的波长漂移可以用来跟踪吸附过程和薄膜的形成。在这份报告中，我们描述了一种简单的基于光学显微镜的方法，用于监测与镀金衍射光栅的增强透射率相关的一阶衍射峰。利用Bertrand透镜将光栅的衍射象聚焦到CCD相机上，衍射峰的空间位置可以很容易地转换为透射光的光谱特征，而不需要使用分光计。当样品被p偏振光照射时，表面等离子体激元峰表现为增强透过率的区域，峰位置反映了金属界面的局部介电性质，包括薄膜的存在。对于具有氧化硅薄膜的样品，使用衍射峰证明了跟踪等离子体激元峰位置并因此测量膜厚度的能力。然后将实验结果与用严格耦合波分析模拟方法计算的薄膜镀膜光栅的光学衍射进行了比较。
Surface plasmon resonance enhanced transmission through metal-coated nanostructures represents a highly sensitive yet simple method for quantitative measurement of surface processes and is particularly useful in the development of thin film and adsorption sensors. Diffraction-induced surface plasmon excitation can produce enhanced transmission at select regions of the visible spectrum, and wavelength shifts associated with these transmission peaks can be used to track adsorption processes and film formation. In this report, we describe a simple optical microscope-based method for monitoring the first-order diffracted peaks associated with enhanced transmission through a gold-coated diffraction grating. A Bertrand lens is used to focus the grating's diffraction image onto a CCD camera, and the spatial position of the diffracted peaks can be readily transformed into a spectral signature of the transmitted light without the use of a spectrometer. The surface plasmon peaks appear as a region of enhanced transmission when the sample is illuminated with p-polarized light, and the peak position reflects the local dielectric properties of the metal interface, including the presence of thin films. The ability to track the position of the plasmon peak and, thus, measure film thickness is demonstrated using the diffracted peaks for samples possessing thin films of silicon oxide. The experimental results are then compared with calculations of optical diffraction through a model, film-coated grating using the rigorously coupled wave analysis simulation method.