Micro and Nano-scale Photonic and Plasmonic Crystal based Thin Film Sensors

今天，在从生物医学诊断到环境监测的各种应用中，对便携式、灵敏、快速和准确的传感器的需求日益增长；例如，用于检测危险化合物或采样和分析纳米体积的生物分子和流体。今天，微米和纳米尺度的光子传感器作为一种有吸引力的解决方案出现了，以满足这些需求。为了满足这一需求，几种片上集成光子微传感器系统正在迅速发展，其中包括基于光子晶体、表面等离子体共振(SPR)、光波导和光纤光栅的平台。特别是，基于硅基光子晶体和基于金纳米颗粒的等离子体晶体传感器能够为不同的应用提供高灵敏度和设计灵活性，同时提供与现有器件技术集成的能力。然而，可靠的制造和集成现在才刚刚开始实现，目前的研究努力正在展示实际应用。提出的研究工作的主要目标是针对特定的应用构建新型的基于光子晶体和等离子体晶体的传感器。第一个方面是继续开发一种新型的微压传感器，该传感器基于采用平面绝缘体上硅技术制造的悬浮光子晶体波导，该技术已申请美国专利。从插入心脏的导管压力传感器、心脏消融手术和恶劣的环境监测等几个领域，都需要不基于电输入的微压传感器的小型化。芯片实验室设备还需要在微流控通道内嵌入微压力传感器，以监控入口和出口压力。在拟议的研究中，光子晶体微压力传感器将针对这些应用而设计，并在我们基于CFI的微传感器设备中进行表征，该设备具有同时进行光学和机械测量的独特能力。在研究项目的另一个方面，生物兼容薄膜聚合物以及特定功能化的表面将被结合到硅基光子晶体和金纳米粒子基等离子体晶体中，用于检测癌症标志物的高灵敏和特定的生物传感器。我们展示了具有近红外SPR的新型金纳米粒子阵列，它们潜在地比它们的可见光对应物更敏感，并且也可以根据阵列的相互作用进行调节。将生物相容水凝胶与光子晶体、光栅和金纳米粒子等离子体晶体相结合，研制出了薄膜pH传感器。到目前为止，我们目前的工作已经显示出改进的灵敏度和选择性，以及将这些传感器与所需检测目标集成的能力。在红外线下工作，可以集成强大的光电子技术，同时获得高灵敏度设备。拟议的跨学科研究的性质需要与西安大略大学的物理、化学工程和机械工程系以及其他大学合作伙伴进行合作。由于拟议研究的一个重要目标是生产针对特定实际应用的微传感器平台，因此已经与行业合作伙伴(基于导管的微压力传感器)和临床医生(癌症标志物检测)建立了合作关系。拟议研究的重要成果将是微型、高灵敏度和特定的光学传感器的可用性，这些传感器需要更快、更便携和准确的诊断。

There is increasing demand today for portable, sensitive, fast and accurate sensors in various applications ranging from bio-medical diagnostics to environmental monitoring; for example to detect hazardous compounds or to sample and analyse nanoscopic volumes of biological molecules and fluids. Micro and nano-scale photonic sensors have emerged today as an attractive solution to address these needs. Several on-chip integrated photonic micro-sensor systems are being rapidly developed to address this need including platforms based on photonic crystals, surface plasmon resonance (SPR), optical waveguide, and optical fiber gratings. In particular silicon based photonic crystal and gold nanoparticle based plasmonic crystal sensors are capable of providing high sensitivities and flexibility in design for different applications while providing the ability to integrate with existing device technologies. However the reliable fabrication and integration are only now beginning to be realized and current research efforts are into demonstrating practical applications. The main objective of the proposed research work is to build novel photonic crystal and plasmonic crystal based sensors targeted for specific applications. The first aspect will be to continue development of a novel micro-pressure sensor based on a suspended photonic crystal waveguide fabricated using planar Silicon-On-Insulator technology for which a US patent has been filed. Miniaturization of micro-pressure sensors which are not based on electrical inputs are needed in several areas ranging from catheter based pressure sensors inserted in heart, cardiac ablation surgery and harsh environmental monitoring. Lab-on-chip devices also require embedded micro pressure sensors inside microfluidic channels for monitoring inlet and outlet pressures. In the proposed research photonic crystal micro-pressure sensors will be designed for these applications and characterized in our CFI based micro-sensor facility which has the unique capability of simultaneous optical and mechanical measurements. In another aspect of the research project, bio-compatible thin film polymers along with specifically functionalized surfaces will be incorporated into silicon based photonic crystal and gold nanoparticle based plasmonic crystals for highly sensitive and specific bio-sensors for cancer markers detection. We have demonstrated novel gold nanoparticle arrays with SPR in the near infra-red spectrum which are potentially more sensitive than their visible counterparts and also tunable based on array interaction. Thin-film pH sensors have been developed by combining bio-compatible hydrogels with photonic crystals, gratings and gold nanoparticle plasmonic crystals. Our current work to date has shown improved sensitivities and selectivity and ability to integrate these sensors with required detection targets. Working in the infra-red enables integration of robust photonics technology while attaining high sensitivity devices. The nature of the proposed research in interdisciplinary in nature requiring collaborations with the physics, chemical engineering and mechanical engineering departments at the University of Western Ontario and other university partners. Since an important aim of the proposed research is to produce micro-sensor platforms targeted for specific practical applications, collaborations with both an industry partner (catheter based micro-pressure sensors) and clinician (cancer marker detection) have been established. The significant outcome of the proposed research will be the availability of miniature, highly sensitive and specific optical sensors which are in demand for faster, portable and accurate diagnostics.