Open AccessTime-resolved HO2 detection with Faraday rotation spectroscopy in a photolysis reactor
Author(s) -
Chu C. Teng,
Chao Yan,
Aric Rousso,
Hongtao Zhong,
Timothy Y. Chen,
Eric Zhang,
Yiguang Ju,
Gerard Wysocki
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.413063
Subject(s) - faraday effect , zeeman effect , spectroscopy , diamagnetism , photodissociation , absorption spectroscopy , optics , materials science , magnetic field , absorption (acoustics) , laser , faraday cage , faraday rotator , sensitivity (control systems) , analytical chemistry (journal) , physics , chemistry , photochemistry , chromatography , quantum mechanics , electronic engineering , engineering
Faraday rotation spectroscopy (FRS) employs the Faraday effect to detect Zeeman splitting in the presence of a magnetic field. In this article, we present system design and implementation of radical sensing in a photolysis reactor using FRS. High sensitivity (100 ppb) and time resolved in situ HO 2 detection is enabled with a digitally balanced acquisition scheme. Specific advantages of employing FRS for sensing in such dynamic environments are examined and rigorously compared to the more established conventional laser absorption spectroscopy (LAS). Experimental results show that FRS enables HO 2 detection when LAS is deficient, and FRS compares favorably in terms of precision when LAS is applicable. The immunity of FRS to spectral interferences such as absorption of hydrocarbons and other diamagnetic species absorption and optical fringing are highlighted in comparison to LAS.