Trace detection of NO_2 by frequency-modulation-enhanced magnetic rotation spectroscopy

This is the authors' abstract. We don't add key points for this paper.

Frequency-modulation-enhanced magnetic rotation spectroscopy has been shown to be a sensitive and selective technique for detecting local concentrations of gaseous NO2. Detection levels of 20 parts in 109 have been achieved in the laboratory (in the presence of larger ambient atmospheric levels). Simple signal-processing algorithms, demonstrated here, promise detection levels at the parts-in-1012 level. Improvements are suggested for further optimization of the technique, and the effects of background atmospheric NO2 levels are discussed.