Broadband Terahertz Polarimetry for Photonic and Biomedical Applications

提案题目：光子和生物医学应用的宽带太赫兹偏振测量机构：华盛顿大学。提议的项目将在各种类型物体和材料的成像和传感应用方面做出重大贡献，并将为健康监测、国土安全和医疗应用做出重大贡献。太赫兹技术的广泛科学重要性得到了大量研究项目和出版物的证明，这些研究项目和出版物致力于开发太赫兹计量技术，用于广泛的应用，包括医学成像，有机和聚合物材料科学，以及手性分子，氨基酸和超材料的研究。特别是，偏振方法将有助于理解物理相互作用机制和器件物理在一系列应用中的应用。我们的工作包括支持向更广泛的研究界积极传播极化能力。此外，这个项目的结构是为了增加本科生和研究生在华盛顿大学的研究机会，通过为学生提供太赫兹偏振方法的仪器学家培训。此外，本项目的实验结果和研究成果将以客座讲座的形式在光子学研究生课程中传播。最后，在整个项目中，我们将努力在本科和研究生阶段识别和招募女性、残疾和代表性不足的少数民族学生。偏振测量和椭偏测量在许多基础科学领域都是研究新材料特性的重要研究技术，它们也有直接的工业和生物医学应用。目前，太赫兹频段的宽带偏振测量存在几个明显的局限性：(1)当前的太赫兹偏振测量技术只能提供粗糙的偏振分辨率和正交偏振通道之间的小隔离，这在很大程度上是由于(2)校准太赫兹偏振计的能力差，这是由于外部偏振器的高频率相关功率损耗；此外(3)目前的太赫兹偏振测量技术需要将外偏振器旋转到预定的固定角度和位置，这给系统带来了较低的测量速度和旋转偏振器放置的不准确性。我们建议开发一种新型宽带太赫兹偏振计，它结合了太赫兹源和探测器技术的两项最新进展：a .气体等离子体中产生的太赫兹波的复杂极化的相干控制，B.使用新型全极化宽带太赫兹光谱装置测量样品诱导的椭圆性和交叉极化。整合这两种技术，我们将展示一个极化敏捷太赫兹偏振测量系统，能够研究各种天然和人造目标的交叉极化和手性。我们将特别展示新的偏振计在两个重要应用中的应用，即健康和烧伤哺乳动物皮肤组织的诊断和基于石墨烯和纳米结构材料的光子器件的表征。

Proposal Title:Broadband Terahertz Polarimetry for Photonic and Biomedical AppllicationsInstitution: University of WashingtonThe proposed project will make significant contributions in imaging and sensing applications of various types of objects and materials and will contribute significantly to health monitoring, homeland security and medical applications. The broad scientific importance of terahertz technology is attested by the number of research programs and publications working to develop terahertz metrology techniques for a broad range of applications, including medical imaging, organic and polymer material science, and study of chiral molecules, amino acids and metamaterials. In particular, polarimetric methods will contribute to an understanding of physical interaction mechanisms and device physics in a range of applications. Our effort includes support for active dissemination of polarimetric capability to the broader research community. Moreover, this project is structured so as to enhance undergraduate and graduate research opportunities at the University of Washington, by providing training to student instrumentalists in terahertz polarimetric methods. Additionally, experimental results and research findings through this project will be disseminated in the form of guest lectures in a graduate-level course in Photonics. Finally, throughout this project, we will endeavor to identify and recruit female, disabled and under-represented minority students, at both undergraduate and graduate levels. Polarization measurement and ellipsometry are essential research techniques for investigating properties of new materials in many areas of basic sciences, which also find immediate industrial and biomedical applications. Broadband polarization measurement in the terahertz frequency regime presently suffers from several significant limitations: (1) Current terahertz polarimetry techniques offer only coarse polarization resolution and small isolation between orthogonal polarization channels, due in significant part to (2) poor ability to calibrate THz polarimeters, as a results of high frequency-dependent power loss in external polarizers; moreover (3) current terahertz polarimetry techniques require rotation of external polarizers to pre-determined fixed angles and positions, which burdens the system with lower measurement speed and inaccuracies in rotational polarizer placement.We propose development of a novel broadband terahertz polarimeter that combines two recent advancements in terahertz source and detector technology: A. Coherent control of complex polarizations of terahertz waves generated in gas plasmas, and B. Measurement of sample-induced ellipticity and cross-polarization using a novel full polarimetric broadband terahertz spectroscopy setup. Integrating these two techniques, we will demonstrate a polarization-agile terahertz polarimetry system capable of investigating cross-polarization and chirality of a wide variety of natural and manufactured targets. We will in particular demonstrate applications of the new polarimeter in two important applications, namely diagnosis of healthy and burned mammalian skin tissue and characterization of photonic devices based on graphene and nano-stuctured materials.