Hybrid Plasmonic Structures: From Photonic Devices to Bio-sensors

近年来，在光学和红外频率上使用金属结构有了强劲的复苏。这在很大程度上是由于表面等离子激元（SPPs）的使用，随着我们在纳米尺度上沉积和塑造物质（特别是金属）的能力不断提高，SPPs成为可能。spp是局限于金属和电介质之间界面的表面波。这些表面波为研究人员提供了有趣的特性：它们可以被限制在极小的尺寸内，表现出尖锐的强度，并表现出强烈的共振。这些特性促使研究人员考虑将SPPs用于各种应用，从紧凑型光子元件和生物传感器到光热和光伏器件。然而，要将spp转变为一种通用技术，必须应对某些挑战。这些挑战中最主要的是：1)需要优化两个相反因素之间的关系：损耗（传播距离）和约束（模式大小）；2)需要多种与硅兼容的功能性等离子体器件；3)等离子体器件除了支持横向磁（TM）模式外，还需要支持横向电（TE）模式，特别是在生物传感应用中。我们提出的计划的长期目标是为这些挑战提供一些答案。为此，最近我们的小组首次提出使用被动混合等离子体（HP）结构作为SPP损耗与约束问题的优化解决方案。此外，HP结构是硅兼容的，支持TM和TE模式。我们将通过建立一个专门提高我们对被动HP结构及其支持的各种模式的知识的计划，以及通过设计、制造、测试和表征各种基于HP架构的被动、紧凑和功能性光子和生物等离子体器件，来实现我们的长期目标。这里提出的方案的成功完成预计将对下一代光学和生物医疗设备的设计产生重大影响。

In recent years the use of metallic structures at optical and infrared frequencies has enjoyed a strong resurgence. This is in large part due to the use of surface plasmon polaritons (SPPs), enabled with our continually improving ability to deposit and shape matter, particularly metals, at the nano-scale. SPPs are surface waves confined to the interface between a metal and a dielectric. These surface waves provide researchers with intriguing properties: they can be confined to exceedingly small dimensions, exhibit sharp intensities, and display strong resonances. These properties have motivated researchers to consider the use of SPPs for various applications ranging from compact photonic components and biosensors to photothermal and photovoltaic devices. However, to transform the SPPs to a versatile technology, certain challenges must be met. Chief among these challenges are: 1) the need to optimize the relation between two opposing factors: losses (propagation distance) and confinement (mode size); 2) the need for a variety of functional plasmonic devices that are silicon compatible; the 3) the need for plasmonic devices to support transverse electric (TE) mode in addition to the transverse magnetic (TM) mode, particularly for biosensing applications. The long term objective of our proposed program is to provide some answers to these challenges. To this end, recently our group was the first to propose the use of a passive hybrid plasmonic (HP) structure as an optimized solution to the problem of SPP loss versus confinement. Moreover, the HP structure is silicon compatible and supports both the TM and TE modes. We will achieve our long range objective by establishing a program which specifically advances our knowledge of the passive HP structure and various modes that it supports, and by designing, fabricating, testing, and characterizing a variety of passive, compact, and functional photonic and bio-plasmonic devices based on the HP architecture. Successful completion of the program proposed here is expected to have a great impact on the design of the next generation of optical and bio-medical devices.