Terahertz Absorption Spectroscopy for Quantitative Detection of Combustion Intermediates and Pollutant Emissions

先进的燃烧系统，包括燃气轮机、内燃机和熔炉，通常需要连续监测废气成分以进行控制和优化，从而实现高效率和低排放。在该项目中，将开发一种传感器，用于检测燃烧过程中重要的排放物和中间物质。该传感器基于气体燃烧分子对太赫兹（THz）波辐射的吸收，称为THz波吸收光谱。传感器将使用硅微电子学设计，目标化合物的THz光谱将被发现和表征。该传感器将在燃烧环境中进行演示。该项目的成果将影响气体传感重要的广泛领域，例如，该研究团队将开发通过太赫兹波吸收在燃烧环境中进行定量形态测量所需的科学基础和技术。对于燃烧中的许多感兴趣的物种，与分子旋转相关的共振频率在太赫兹频带中，并且这些跃迁的吸收强度通常大于在微波或红外区域中发现的那些。此外，太赫兹波吸收有效地免受燃烧环境中阻碍红外吸收的颗粒和气溶胶的散射的影响。该项目涉及三项研究任务。首先，挥发性有机化合物和三种含氮物质的太赫兹波光谱将在180-360 GHz的频率范围内进行实验研究和表征。其次，将在相同的频率范围内设计、制造和测试用于光谱学的太赫兹辐射源，该辐射源由使用标准硅技术制造的单个微芯片组成。最后，该传感器将通过测量燃烧器排气烟囱中的排放来演示。作为该项目的一部分开发的科学和技术具有强大的商业化潜力，因为工业需要在燃烧中进行气体传感，以及电子太赫兹技术相对于竞争的红外传感器技术的低成本。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Advanced combustion systems, including gas turbines, internal combustion engines, and furnaces, often require continuous monitoring of exhaust gas composition for control and optimization, to achieve high efficiency and low emissions. In this project, a sensor will be developed for the detection of emissions and intermediate species important in combustion processes. The sensor is based on the absorption of terahertz (THz) wave radiation by the gaseous combustion molecules, known as THz wave absorption spectroscopy. A sensor will be engineered using silicon microelectronics, the THz spectroscopy of target compounds will be discovered and characterized. The sensor will be demonstrated in a combustion environment. The outcome of this project will impact a broad range of sectors where gas sensing is important, e.g., energy, transportation, manufacturing, oil and gas, and air quality control.The research team will develop the scientific foundation and technology necessary for quantitative speciation measurements in combustion environments via THz wave absorption. For many species of interest in combustion, the resonant frequencies associated with molecular rotations are in the THz frequency band, and the absorption strength of these transition is often larger than those found in either the microwave or infrared regions. Additionally, THz wave absorption is effectively immune to scattering from particles and aerosols that hinder infrared absorption in combustion environments. The project addresses three research tasks. First, the THz wave spectroscopy of volatile organic compounds and three nitrogen-containing species will be experimentally investigated and characterized in the 180-360 GHz frequency range. Second, a THz radiation source for spectroscopy, consisting of single microchip fabricated using standard silicon technology, will be designed, fabricated, and tested in the same frequency range. Finally, the sensor will be demonstrated by measuring emissions in a burner exhaust stack. The science and technology developed as part of this project has a strong potential for commercialization due to the industrial need for gas sensing in combustion and the low cost of electronic THz technologies relative to competing infrared-based sensor technologies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.