标题： 用于空气污染物检测的太赫兹原型 显示英文标题

标题： Terahertz prototype for air pollutants detection

摘要： 在这项工作中，我们提出了一种利用太赫兹时域光谱（THz-TDS）的原型装置，用于研究气态化合物。该系统便携，并允许进行远程测量。我们首次使用该原型，在广泛的太赫兹范围内表征了纯二氯甲烷和氯仿这两种已知为非常短寿命物质（VSLS）的污染物，它们对臭氧消耗有显著贡献。太赫兹范围能够选择性地检测与其分子旋转运动相关的吸收线，我们还提供了理论确认。然后，我们研究了由上述两种含氯化合物与两种广泛分布的挥发性污染物（丙酮和甲醇）混合而成的多组分混合物的光学响应。对于这些初步测量，我们专门开发了该装置以适应实验室条件，其中物质被直接注入气室回路中。最后，我们修改了原型装置，以确保通过一根长管和适当开发的抽吸系统，直接从环境大气中抽取空气进入气室。实验室和现场条件下对混合物的分析表明，该原型装置结合本研究采用的方法可以同时识别和量化大气中的单一成分。所获得的结果为开发和应用高效便携式基于太赫兹的传感器以实现多组分环境污染物的远程检测开辟了新的可能性。 显示英文摘要

摘要： In this work, we propose a prototype set-up exploiting terahertz time-domain spectroscopy (THz-TDS) to investigate gaseous compounds. The system is portable and allows to perform remote measurements. We used the prototype to characterise for the first time in literature over a broad THz range, pure dichloromethane and chloroform, two pollutants known as very short-lived substances (VSLS) that strongly contribute to ozone depletion. The THz range allows selectively detecting their absorption lines related to the rotational molecular motion for which we also present the theoretical confirmation. Then, we investigate the optical response of a multi-component mixture achieved with the two aforementioned chlorine-based compounds mixed with two widely distributed volatile pollutants (acetone and methanol). For these first measurements, we developed the set-up specifically for laboratory condition in which the substances are directly injected into the gas-cell circuit. Finally, we modified the prototype to ensure that the ambient atmosphere is drawn directly into the gas cell via a long pipe and a suction system opportunely developed. The analysis of the mixtures in both laboratory and in-field conditions demonstrates that the prototype together with the approach employed in this work can simultaneously identify and quantify single components in the atmosphere. The results obtained open up new possibilities for the development and applications of an efficient portable THz-based sensor for the remote detection of multi-component environmental contaminants.