| Title | Amplitude-Modulated Cavity-Enhanced Absorption Spectroscopy with Phase-Sensitive Detection: A New Approach Applied to the Fast and Sensitive Detection of NO2 |
| Authors | Zhou, Jiacheng Zhao, Weixiong Zhang, Yang Fang, Bo Cheng, Feihu Xu, Xuezhe Ni, Shichuan Zhang, Weijun Ye, Chunxiang Chen, Weidong Venables, Dean S. |
| Affiliation | Chinese Acad Sci, Lab Atmospher Physicochem, Anhui Inst Opt & Fine Mech, HFIPS, Hefei 230031, Anhui, Peoples R China Univ Sci & Technol China, Hefei 230026, Anhui, Peoples R China Peking Univ, Coll Environm Sci & Engn, Beijing 100871, Peoples R China Univ Littoral Cote dOpale, Lab Physicochim Atmosph, F-59140 Dunkerque, France Univ Coll, Sch Chem, Cork T23 XE10, Ireland Univ Coll, Environm Res Inst, Cork T23 XE10, Ireland |
| Keywords | RING-DOWN SPECTROSCOPY SPECTROMETER TD-CRDS CHEMICAL AMPLIFICATION NITROGEN-DIOXIDE PEROXY-RADICALS MIXING RATIOS AMBIENT NO2 REAL-TIME IN-SITU CHEMISTRY |
| Issue Date | Feb-2022 |
| Publisher | ANALYTICAL CHEMISTRY |
| Abstract | Accurate and sensitive measurements of NO2 play an extremely important role in atmospheric studies. Increasingly, studies require NO2 measurements with parts per trillion by volume (pptv-level) detection limits. Other desirable instrument attributes include ease of use, long-term stability, and low maintenance. In this work, we report the development of an amplitude-modulated multimode-diodelaser-based cavity-enhanced absorption spectroscopy (AM-CEAS) system operating at 406 nm that uses phase-sensitive detection for extremely sensitive NO2 detection. The laser was TTL-modulated at 35 kHz. The mirror reflectivity was determined to be 99.985% based on the ring-down time measurement. The cavity base length was 47.5 cm, giving an effective absorption pathlength of similar to 3.26 km. AM-CEAS achieved a 1 sigma detection precision of 35 pptv in a 1 s data acquisition time (4.98 x 10(-10) cm(-1)), over 4 times lower than that attained using a ring down approach and the same optical system. The AM-CEAS precision improved to 8 pptv over a data acquisition time of 30 s (1.14 x 10(-10) cm(-1)). The AM-CEAS method with the multimode diode laser integrates the advantages of high light injection efficiency like on-axis alignment cavity ring-down spectroscopy, low cavity-mode noise like off-axis alignment CEAS, and narrow-bandwidth high-sensitivity weak signal detection of modulation spectroscopy, providing a powerful, straightforward, and general method for ultrasensitive absorption and extinction measurements. |
| URI | http://hdl.handle.net/20.500.11897/638287 |
| ISSN | 0003-2700 |
| DOI | 10.1021/acs.analchem.1c05484 |
| Indexed | SCI(E) |
| Appears in Collections: | 环境科学与工程学院 |
