Nanophotonics in low cost applications

这项研究的目标是研究具有新的或增强的光学性质的纳米结构，并围绕它们建立低成本的生物传感应用。在不同的纳米结构中，纳米线和表面等离子体特别令人感兴趣。纳米线可以将光子和载流子限制在两个维度，同时允许它们在第三个维度传播。表面等离子体是一种能在金属-电介质边界表面共振导波的导波。我们已经利用表面等离子体二维纳米光栅开发了结构颜色，并表明颜色对材料的折射率或表面的变化很敏感。Discovery项目的目标将是整合我们的两个平台，以构建低成本的光电子应用。这项研究将涉及基础研究、材料表征和开发低成本应用的工程设计。 在短期内，我们将研究制造将我们的芯片与手机集成在一起的低成本生化传感器。将考虑三种应用，即检测水中的污染物和病原体；检测食品中的病原体，特别是肉类加工中的病原体，以方便安大略省的食品生产商；以及检测环境中的微量爆炸物。这些应用的主要区别在于芯片的功能化。由于纳米结构在探测器的存在下会生动地改变颜色，传感系统将建立在手机周围，使用相机成像和处理器进行分析。芯片的二维分析将被设计和建造，其中每个芯片将被特别地功能化，以结合到一个单一的检测器。芯片将与微流控通道集成在一起，目标检测器将通过这些通道到达芯片，在那里进行捕获和检测。我们还将看看硅纳米线阵列是否可以用于对不同大小的分子进行分类。为了理解这一点，我们将对水在二维周期性纳米结构中的相互作用和流动进行基础研究。这些相互作用将使用核磁共振测量进行研究。据我们所知，还没有进行过这样的研究。手机的其他功能，如GPS和无线连接，也将用于我们的传感系统。例如，对于水污染测试，可以用地理位置标记测试数据，并将结果发送到服务器以在进行测试时创建现场地图。人们还可以想象一个分散的检测系统，在这个系统中，检测到的病原体信息可以通过在线社交门户网站迅速分发给当地人口。这可能导致由“人民为人民”进行的测试。传感器的低成本和小尺寸意味着这些传感器可以很容易地通过无线连接进行分布和联网，以检测爆炸物。由于便携的性质，为马拉松等特殊活动设置设备将很容易。灵感来自《星际迷航》中的三分仪；我们的目标是利用纳米技术的力量和手机无处不在的本质来使这一虚构成为现实。 从长远来看，我们计划通过实验和理论手段来研究这些纳米结构的增强光学性质。将研究用于三维显示的全息图像、用于光学逻辑和太赫兹产生的增强电场和光学非线性等特性。我们还将开发在直接带隙III-V材料(如砷化镓)上创建纳米线阵列的制造和刻蚀方法。将研究新的纳米结构光学和电学性质的模拟方法。

The goals of the research are to investigate nanostructures for new or enhanced optical properties and build low cost biosensing applications around them. Of different nanostructures, nanowires and surface plasmons are of particular interest. Nanowires can confine photons and carriers in two dimensions while allowing them to propagate in the third. Surface plasmons are guided waves which can be resonantly guided on the surface of metal-dielectric boundary. We have developed structural colors using surface plasmonic two dimensional nano-gratings and shown that the colors are sensitive to refractive index of the material or changes to the surface. The goal of the Discovery project will be integrate our two platforms for building low cost photonics applications. The research will involve both fundamental studies and material characterizations and engineering designs for developing low cost applications. Over the short term, we will investigate building low cost bio-chemical sensors integrating our chips with cell-phones. Three applications namely detection of pollutants and pathogens in water; detection of pathogens in food especially in meat processing to facilitate the food producers in Ontario; and detection of traces of explosives in environment will be considered. The main difference in these applications is the functionalization of the chips. Since the nanostructures change color vividly in presence of detectants, the sensing system will be built around cell-phones using the cameras for imaging and processors for analyzing. 2-dimensional assay of chips will be designed and built where each chip will be functionalized specifically to bind to one single detectant. The chips will be integrated with micro-fluidic channels and the targeted detectants will travel through these channels to the chips where capture and detection will occur. We will also see whether the silicon nanowire arrays can be used for sorting molecules of different sizes. In order to understand this, fundamental studies will be done at how water interacts and flows within two dimensional periodic nanostructures. These interactions will be studied using nuclear magnetic resonance measurements. To our knowledge, no such study has been carried. Other features of cell-phones like the GPS and the wireless connectivity will also be used in our sensing system. For example, for water pollution testing, the test data can be tagged with the geographical locations and the results sent to a server to create in-situ maps as testing is being done. One can also imagine a decentralized testing system where information of pathogens detected can be quickly distributed to the local population through online social portals. This could result in testing done by “people for the people”. The low cost and small form factor of the sensors means that these could easily be distributed and networked through the wireless connectivity for detecting explosives. Setting up the devices for special events like marathons will be easy due to the portable nature. Inspired by the “tricorder” in Star-trek; our goal is to use the power of nanotechnology and the ubiquitous nature of cell-phones to make this fiction a reality. Over the long term, we plan to investigate these nanostructures for their enhanced optical properties through experimental and theoretical means. Properties like holographic images for three dimensional displays; enhanced electric fields and optical nonlinearities for optical logic and terahertz generation will be investigated. We will also develop fabrication and etching methods for creating nanowire arrays on direct bandgap III-V materials like gallium arsenide. New simulation methods for optical and electrical properties of nanostructures will be investigated.