Nanophotonics in low cost applications

该研究的目标是研究纳米结构的新的或增强的光学特性，并围绕它们建立低成本的生物传感应用。不同的纳米结构，纳米线和表面等离子体是特别感兴趣的。纳米线可以将光子和载流子限制在两个维度上，同时允许它们在第三个维度上传播。表面等离子体激元是一种在金属-电介质界面上共振传播的导波。我们已经开发了结构色使用表面等离子体二维纳米光栅，并表明颜色是敏感的材料的折射率或表面的变化。Discovery项目的目标是整合我们的两个平台，以构建低成本的光子学应用。该研究将涉及基础研究和材料表征以及开发低成本应用的工程设计。 在短期内，我们将研究建立低成本的生物化学传感器集成我们的芯片与手机。该系统可应用于三方面，即检测水中的污染物和病原体;检测食物中的病原体，特别是肉类加工过程中的病原体，以方便安大略的食品生产商;以及检测环境中的爆炸物痕迹。这些应用的主要区别在于芯片的功能化。由于纳米结构在检测剂存在下会生动地改变颜色，因此传感系统将围绕手机构建，使用相机进行成像和处理器进行分析。2-将设计和构建芯片的三维测定，其中每个芯片将被特异性地功能化以结合到一个单一的检测物。芯片将与微流体通道集成，并且靶向检测剂将通过这些通道行进到芯片，在芯片中将发生捕获和检测。我们还将看到硅纳米线阵列是否可以用于分选不同大小的分子。为了理解这一点，将对水如何在二维周期性纳米结构中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，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，以在测试进行时创建现场地图。人们还可以想象一个分散的检测系统，在该系统中，检测到的病原体信息可以通过在线社交门户网站快速分发给当地居民。这可能导致"人民为人民"进行测试。传感器的低成本和小尺寸意味着它们可以通过无线连接轻松分布和联网，以检测爆炸物。由于其便携性，为马拉松等特殊活动设置设备将很容易。受《星际迷航》中“三录仪”的启发，我们的目标是利用纳米技术的力量和手机无处不在的特性，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研究这些纳米结构的增强光学特性。将研究三维显示器的全息图像，光学逻辑和太赫兹产生的增强电场和光学非线性等特性。我们还将开发制造和蚀刻方法，用于在直接带隙III-V材料（如砷化镓）上创建纳米线阵列。 纳米结构的光学和电学性质的新的模拟方法将被研究。

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.