Sub-wavelength imaging and spectroscopy using terahertz plasmons

智力优势：太赫兹科学技术近年来已成为最激动人心的研究前沿之一。电磁频谱的这一长期被忽视的部分已经引起了人们的极大关注，因为它有许多可能的应用，从基础科学到应用工程。太赫兹传感是一个重要的研究领域，它利用材料独特的光谱特征进行检测和识别。太赫兹光谱范围丰富，许多不同的物质具有强烈和独特的吸收指纹。然而，太赫兹系统相对较差的灵敏度阻碍了这一领域的发展。人们可以将其与最先进的中红外吸收光谱进行比较，对于中红外吸收光谱，可以达到万亿分之一的检测水平，或者可以与表面增强拉曼散射进行比较，表面增强拉曼散射可以用于检测单个分子。为了在太赫兹范围内获得相当的灵敏度，需要新的成像和光谱学配置。这项提议的目的是开发敏感的新技术，用于使用太赫兹辐射的近场传感和光谱分析。方法是利用已经在光学频率上演示的技术，基于在尖锐的金属尖端附近使用等离子激元增强。这项研究计划的智力价值将是开发的新技术，以及它们为分子晶体和生物分子络合物中的极低频拉曼活性模式提供了新的窗口。广泛的影响：这项工作将在太赫兹科学和技术领域以及许多其他光学物理领域产生广泛影响。它将使新的传感技术成为可能，这些技术具有重要的技术意义。这将为甚低频拉曼模式的研究提供一条新的途径，这可能对理解生物分子动力学具有重要意义。它还将提供一个多学科计划，培训新学生在飞秒光学、太赫兹物理和分子传感方面的知识。

ECCS-0724996Mittleman, DanielWilliam Marsh Rice UniversityIntellectual Merits:Terahertz science and technology has become one of the most exciting research frontiers in recent years. This long-neglected portion of the electromagnetic spectrum has attracted a great deal of attention, because of the many possible applications, ranging from basic science to applied engineering. One important research area is terahertz sensing, which exploits the unique spectroscopic signatures of materials for detection and identification. The terahertz range is spectroscopically rich, with many different substances possessing strong and unique absorption fingerprints. The field has been hampered, however, by the relatively poor sensitivity of terahertz systems. One may compare with state-of-the-art mid-infrared absorption spectroscopy, for which parts per trillion detection levels are attainable, or to surface-enhanced Raman scattering, which can be used to detect a single molecule. In order to achieve comparable sensitivity in the terahertz range, new configurations for imaging and spectroscopy are needed. The aim of this proposal is to develop sensitive new techniques for near-field sensing and spectroscopy using terahertz radiation. The approach is to exploit techniques that have been demonstrated at optical frequencies, based on the use of plasmonic field enhancements near sharp metal tips. The intellectual merit of this research program will be the new techniques that are developed, as well as the new window they provide on very low frequency Raman-active modes in molecular crystals and bio-molecular complexes.Broader Impacts:This work will have a broad impact in the area of terahertz science and technology, and in numerous other areas of optical physics. It will enable new sensing techniques, which are of great technological importance. It will provide a new avenue for the study of very low frequency Raman modes, which may be of fundamental importance in the understanding of biomolecular dynamics. It will also provide a multidisciplinary program for training new students in femtosecond optics, terahertz physics, and molecular sensing.