Terahertz particle-in-liquid sensing with spoof surface plasmon polariton waveguides
Terahertz particle-in-liquid sensing with spoof surface plasmon polariton waveguides
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DOI：
10.1063/1.4998566
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发表时间：
2017-11-01
期刊：
影响因子：
5.6
通讯作者：
Maier, Stefan A.
中科院分区：
文献类型：
--
作者：
Ma, Zhijie;Hanham, Stephen M.;Maier, Stefan A.
提出了一种基于表面等离子体激元（SPPs）的太赫兹（THz）电磁波高灵敏度微流体传感技术。通过在欺骗SPP波导中集成微流体通道，我们利用这些高度受限的电磁模式来创建用于液体介电传感的平台。我们的设计包括一个多米诺骨牌波导，也就是说，一系列周期性排列的矩形金属块上的金属表面，支持传播的欺骗SPP。通过数值模拟，我们证明了欺骗SPPs的传输沿着波导是非常敏感的液体流过微流体通道交叉波导的折射率，以给出一个纳升规模的相互作用体积。此外，通过利用多米诺波导的基本欺骗SPP模式的金属块的横向宽度的不敏感性，我们设计了一个锥形波导能够实现进一步的限制的电磁场。使用这种方法，我们证明了在液体中流动的单个亚波长微粒的高灵敏度检测。这些结果对于创建基于欺骗SPP的THz芯片上实验室微流体设备是有希望的，该设备适合于分析缓冲溶液中的生物液体如蛋白质和循环肿瘤细胞。(C)2017年作者。
We present a highly sensitive microfluidic sensing technique for the terahertz (THz) region of the electromagnetic spectrum based on spoof surface plasmon polaritons (SPPs). By integrating a microfluidic channel in a spoof SPP waveguide, we take advantage of these highly confined electromagnetic modes to create a platform for dielectric sensing of liquids. Our design consists of a domino waveguide, that is, a series of periodically arranged rectangular metal blocks on top of a metal surface that supports the propagation of spoof SPPs. Through numerical simulations, we demonstrate that the transmission of spoof SPPs along the waveguide is extremely sensitive to the refractive index of a liquid flowing through a microfluidic channel crossing the waveguide to give an interaction volume on the nanoliter scale. Furthermore, by taking advantage of the insensitivity of the domino waveguide's fundamental spoof SPP mode to the lateral width of the metal blocks, we design a tapered waveguide able to achieve further confinement of the electromagnetic field. Using this approach, we demonstrate the highly sensitive detection of individual sub-wavelength micro-particles flowing in the liquid. These results are promising for the creation of spoof SPP based THz lab-on-a-chip microfluidic devices that are suitable for the analysis of biological liquids such as proteins and circulating tumour cells in buffer solution. (C) 2017 Author(s).