Terahertz Plasmonics for Linear and Nonlinear Spectroscopy and Sensing

用于线性和非线性光谱和传感的太赫兹等离子体

• 批准号: 1505536
• 负责人: Daniel Mittleman
• 金额: $ 40万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505536&HistoricalAwards=false
• 关键词: Terahertz; Plasmonics; Linear; Nonlinear; Spectroscopy

Terahertz science and technology has become one of the most exciting research frontiers in recent years. This long-neglected portion of the electromagnetic spectrum (with frequencies ranging from about 0.1 to 5 THz, which corresponds to wavelengths from about 0.06 to 3 mm) has attracted a great deal of attention, because of the many possible research and technology applications. One important area is terahertz sensing, which exploits the unique spectroscopic signatures of materials for detection and identification. Recent research has shown that the terahertz range is spectroscopically rich, with many different substances possessing strong and unique absorption fingerprints. Sensitive sensing technologies would therefore have wide-ranging applications, in areas as diverse as food monitoring and chemical weapons detection. However, the field has been hampered by the relatively poor sensitivity of terahertz systems. By contrast, state-of-the-art mid-infrared absorption spectroscopy achieves parts-per-trillion detection levels, and surface-enhanced Raman scattering in the visible or near- infrared can be used to detect the spectroscopic signature of a single molecule. The aim of this research program is to demonstrate new techniques for sensing and spectroscopy using terahertz pulses, including pulses with very high peak electric fields. The approach is to build on recent work which explored the giant enhancements of fields that can occur in the local environment of small metallic structures. These ideas will be combined with newly developed techniques for high-energy terahertz pulse generation. This combination will enable the generation of extremely high local field strengths, opening up a new realm for extreme light-matter interactions in the terahertz range, and pointing the way towards vast improvements in the sensitivity of terahertz sensing systems.This comprehensive three-year research program has several important goals. It will pioneer the development of sensitive new techniques for time-resolved spectroscopic studies based on nonlinear interactions induced by strong terahertz fields. By generating the highest terahertz fields yet reported and studying their interaction with materials, this work will establish the possibility of exploiting higher-order nonlinear interactions such as Raman scattering, which have been essentially absent from the THz literature. It will also demonstrate new techniques for sensing based on these nonlinear interactions, which are of great technological importance. The scope of the project is defined by two broad research thrusts. The first will investigate the new possibilities enabled by plasmonic devices for sensing and manipulation of terahertz waves. This will include the study of metasurfaces, including those fabricated on active substrates which can be switched electrically. It will also involve the use of atomic force microscopy for tip-enhanced near-field spectroscopies including near-field emission spectroscopy. The second thrust will explore the possibilities offered by nonlinear interactions induced by these plasmonic local field enhancements, by integrating these plasmonic devices together with high-intensity terahertz incident fields. Broadly speaking, this work will change the prevailing view of terahertz science, which is generally thought to be confined to the low- field or perturbative limit. By extending the recent breakthrough work on terahertz high-field generation, this project will establish a new discipline of extreme terahertz light-matter interactions.

Terahertz科学技术已成为近年来最令人兴奋的研究领域之一。 电磁频谱的这一长期结束的部分（频率约为0.1至5 THz，对应于大约0.06至3 mm的波长）引起了很多关注，因为许多可能的研究和技术应用。 一个重要的领域是Terahertz传感，它利用了材料的独特光谱特征进行检测和识别。 最近的研究表明，Terahertz范围在光谱上富含，许多不同的物质具有强大而独特的吸收指纹。 因此，敏感的传感技术将在食品监测和化学武器检测的区域中具有广泛的应用。 然而，田耐茨系统的敏感性相对较差，该领域受到了阻碍。 相比之下，最先进的中红外吸收光谱可以使用可见或近红外的表面增强的拉曼散射达到零件的检测水平，可用于检测单个分子的光谱特征。该研究计划的目的是使用Terahertz脉冲（包括具有很高峰值电场的脉冲）来证明用于传感和光谱的新技术。 这种方法是基于最近的工作，探讨了在小型金属结构的当地环境中可能发生的巨大田地增强。 这些想法将与新开发的高能Terahertz Pulse生成的技术结合使用。 这种组合将使极高的本地田野优势产生，为Terahertz系列中极端光的相互作用开辟了一个新领域，并为Terahertz感应系统的敏感性迈出了巨大的改善。这项全面的三年研究计划具有多个重要目标。 它将基于强烈的Terahertz领域引起的非线性相互作用，开发敏感的新技术，以开发时间分辨的光谱研究。通过生成迄今报告的最高的Terahertz领域并研究其与材料的相互作用，这项工作将确定利用高阶非线性相互作用（例如拉曼散射）的可能性，如THZ文献本质上没有。 它还将根据这些非线性相互作用来展示用于感测的新技术，这些非线性相互作用非常重要。 该项目的范围由两个广泛的研究推力定义。第一个将通过等离子体设备来调查新的可能性，以感知和操纵Terahertz波。 这将包括对元额叶的研究，包括在活性底物上捏造的元信息。 它还将涉及将原子力显微镜用于尖端增强的近场光谱，包括近场发射光谱。 第二个推力将通过将这些等离激元设备与高强度的Terahertz入射场一起整合到这些等离子体局部场提高所引起的非线性相互作用所提供的可能性。 从广义上讲，这项工作将改变Terahertz Science的普遍观点，这通常被认为仅限于低场或扰动限制。 通过扩展最近在Terahertz高场一代上的突破性工作，该项目将建立一项新的Terahertz光线相互作用的新学科。