Frequency-Agile Terahertz Spectrometry for Advanced Chemical Sensing

该项目的目标是开发新一代室温太赫兹光谱仪，与现有的先进化学传感技术相比，其带宽显著增加。为此，本文将研究一种新型等离子体外差光谱仪的概念，该概念用具有太赫兹包络层的近红外本振取代传统外差接收机的太赫兹本振。等离子体天线的独特功能是这项创新的关键，它可以将近红外本振和太赫兹信号有效地耦合到半导体纳米结构中，而半导体纳米结构专门设计用于直接混合本振和太赫兹信号。提出的工作的智能优点是一个全新的外差太赫兹光谱仪架构，使用近红外本振代替太赫兹本振在传统外差太赫兹光谱仪中使用。与太赫兹本振相比，近红外本振具有更高的功率、更宽的频率可调性和更窄的线宽，从而显著提高了光谱仪的灵敏度、工作带宽和室温下的光谱分辨率。拟议研究的更广泛影响是开发生物医学传感、药品质量控制、空气污染控制和安全检查的高性能系统，以及通过新的研究生和本科课程、K12活动、招募和保留代表性不足的少数民族来开发教育/推广计划，以增加太赫兹工程师和科学家的供应。

The objective of this program is to develop a new generation of room-temperature terahertz spectrometers with significant bandwidth increase compared to existing technologies for advanced chemical sensing. For this purpose, a novel plasmonic heterodyne spectrometer concept will be investigated which replaces the terahertz local oscillator of traditional heterodyne receivers by a near infrared local oscillator with a terahertz envelope. Unique capabilities of plasmonic antennas are key in this innovation, which enable efficient coupling of the near infrared local oscillator and terahertz signal into the semiconductor nanostructures that are specifically designed to allow direct mixing of the local oscillator and terahertz signal. The intellectual merit of the proposed work is an entirely new heterodyne terahertz spectrometer architecture that uses a near infrared local oscillator instead of the terahertz local oscillator employed in conventional heterodyne terahertz spectrometers. Near infrared local oscillators offer orders of magnitude higher power, wider frequency tunability, and narrower linewidth compared with terahertz local oscillators, leading to a significant improvement in spectrometer sensitivity, operation bandwidth and spectral resolution at room temperature. The broader impacts of the proposed research are developing high performance systems for biomedical sensing, pharmaceutical quality control, air pollution control, and security screening, as well as developing an education/outreach program for increasing the supply of terahertz engineers and scientists through new graduate and undergraduate courses, K12 activities, recruitment and retention of under-represented minorities.