Harnessing electromagnetic surface waves for optical sensing applications

电磁表面波的激发可以对这些波局部化的界面的任一侧上的材料的光学性质非常敏感。因此，电磁表面波非常适合于光学感测应用。事实上，基于表面等离子体激元（SPP）波的光学传感器-这是由金属和介电材料的平面界面支持的电磁表面波-处于与医疗诊断，环境监测和食品安全相关的分析物的无标记和实时检测的最前沿。然而，除了SPP波之外，还有几种其他类型的电磁波似乎有希望用于光学传感应用。例如，Dyakonov波由两种介电材料之间的界面支持，其中至少一种介电材料是各向异性的; Dyakonov-Tamm波由两种介电材料之间的界面支持，其中至少一种介电材料是各向异性的，并且其中至少一种介电材料是非均匀的。这些和其他类型的电磁表面波可能会产生灵敏度超过SPP波的光学传感器。此外，从光学感测应用的角度来看，由非均匀材料支持的电磁表面波特别有吸引力，因为可以在给定频率下激发这些波的多样性;潜在地，可以利用这些多个波来提高灵敏度和特异性，并且一次检测多于一种分析物。提出了理论和数值研究，以调查的各种各向异性和mathally-nonhomogeneous材料的光学传感应用的平面界面支持的电磁表面波的适用性。材料需要是多孔的，以允许分析物到达界面。棱镜耦合和光栅耦合的配置将进行调查，与逆均匀化技术用于估计本构特性的变化，这导致渗透含分析物的流体。这项工作的一个关键组成部分将涉及对宾夕法尼亚州立大学工程科学和力学系的研究访问，该大学是国际知名的电磁表面波和纳米结构材料理论和实验方面的卓越中心。要求为两次研究访问提供资金，以便能够以最高效率执行拟议的项目。

The excitation of electromagnetic surface wave can be acutely sensitive to the optical properties of the materials on either side of the interface to which these waves are localized. Consequently, electromagnetic surface waves are well-suited to optical sensing applications. Indeed, optical sensors based on surface-plasmon-polariton (SPP) waves -- which are electromagnetic surface waves supported by the planar interface of a metal and a dielectric material -- are at the forefront of label-free and real-time detection of analytes related to medical diagnostics, environmental monitoring and food safety. However, in addition to SPP waves, there are several other types of electromagnetic waves which seem promising for optical sensing applications. For examples, Dyakonov waves are supported by the interface between two dielectric materials, at least one of which is anisotropic; and Dyakonov--Tamm waves are supported by the interface between two dielectric materials at least one of which is anisotropic and at least one of which is periodically-nonhomogeneous. These and other types of electromagnetic surface waves could potentially yield optical sensors with sensitivities that exceed those associated with SPP waves. Furthermore, electromagnetic surface waves supported by periodically-nonhomogeneous materials are particularly appealing from the perspective of optical sensing applications because a multiplicity of these waves can be excited at a given frequency; potentially these multiple waves could be harnessed to improve sensitivities and specificities, and to detect more than one analyte at a time. Theoretical and numerical studies are proposed in order to investigate the suitability of electromagnetic surface waves supported by the planar interfaces of various anisotropic and periodically-nonhomogeneous materials for optical sensing applications. The materials are required to be porous to allow analytes to reach the interface. Prism-coupled and grating-coupled configurations will be investigated, with inverse homogenization techniques used to estimate changes in constitutive properties which result from infiltration by analyte-containing fluids. A key component of this work will involve research visits to the Department of Engineering Science and Mechanics at Pennsylvania State University, which is an internationally-renowned centre for excellence in theoretical and experimental aspects of electromagnetic surface waves and nanostructured materials. Funds are requested for two research visits which would enable the proposed project to be undertaken with maximum efficiency.