Physics Department, University of South Florida, Tampa, Florida33620, United States.
Anal Chem. 2023 Feb 21;95(7):3703-3711. doi: 10.1021/acs.analchem.2c04707. Epub 2023 Feb 6.
The detection of ambient outdoor trace hydrocarbons was investigated with a multipass Raman analyzer. It relies on a multimode blue laser diode receiving optical feedback from a retroreflecting multipass optical cavity, effectively creating an external cavity diode laser within which spontaneous Raman scattering enhancement occurs. When implemented with ultra-low-loss mirrors, a more than 20-fold increase in signal-to-background ratio was obtained, enabling proximity detection of trace motor vehicle exhaust gases such as H, CO, NO, CH, CH, CH, and CH. In a 10-min-long measurement at double atmospheric pressure, the limits of detection obtained were near or below 100 ppb for most analytes.
采用多通拉曼分析仪研究了环境室外痕量碳氢化合物的检测。它依赖于多模蓝光激光二极管从回射多通光腔接收光反馈，有效地在其中创建了一个外部腔二极管激光器，在该激光器中发生自发拉曼散射增强。当与超低损耗反射镜一起使用时，获得了超过 20 倍的信号与背景比的提高，从而能够近距离检测痕量机动车废气，如 H、CO、NO、CH、CH、CH 和 CH。在双大气压力下进行的 10 分钟长的测量中，大多数分析物的检测限接近或低于 100 ppb。
