Department of Electrical and Computer Engineering, and Waterloo Institute of Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
Nanotechnology. 2013 Sep 6;24(35):355501. doi: 10.1088/0957-4484/24/35/355501. Epub 2013 Aug 6.
A two-dimensional array of gold nano-patches on a highly reflective mirror is proposed for refractive index sensing based on changes in the reflected colors. The grating on the mirror creates localized surface plasmon resonances resulting in a minimum in the visible reflectance spectra. The wavelength of the resonance can be tuned by changing the width of the nano-patches and is also dependent on the refractive index of the surrounding medium. The color variation due to change in the refractive index is measured and used to realize a simple low-cost sensor with a refractive index resolution better than 10⁻⁵ just using image processing. The efficacy of the proposed sensor is also demonstrated for surface sensing by depositing thin layers of silicon dioxide. The color difference due to the addition of a 3 nm thick layer of silicon dioxide is detectable by the naked eye and deposition thickness of 2 Å can be resolved using image processing.
提出了一种在高反射镜上的金纳米贴片二维阵列，用于基于反射颜色变化的折射率传感。镜面上的光栅产生局域表面等离子体共振，导致可见光反射率光谱中的最小值。通过改变纳米贴片的宽度可以调整共振的波长，并且该波长还取决于周围介质的折射率。通过测量由于折射率变化引起的颜色变化，使用图像处理实现了一种简单的低成本传感器，其折射率分辨率优于 10⁻⁵。还通过沉积二氧化硅的薄层来证明所提出的传感器在表面传感方面的功效。通过肉眼可以检测到添加 3nm 厚的二氧化硅层引起的颜色差异，并且可以使用图像处理分辨出 2Å 的沉积厚度。
