Nitrogen oxides are a group of pollutants present in the atmosphere that affect the environment. NO<sub>2 </sub>contributes to the formation of smog and can be hazardous to human health. It exists in low concentrations in the atmosphere and to detect it, and hence a fast and sensitive apparatus is required for accurate measurements. Cavity ring-down spectroscopy (CRDS) is one such method. It is a sensitive, portable, simple, and yet powerful optical technique. It can detect concentrations in the ppb range by employing a long path length. This is possible by using highly reflective (R &gt; 99.999%) concave mirrors in a cavity, which allows for effective path lengths on the order of 10-50 km. In this experiment, diode lasers are used instead of pulsed lasers in a technique called continuous wave cavity ring-down spectroscopy (CW-CRDS) and an acoustic optical modulator (AOM) is used to generate the pulse. We present the detection of nitrogen dioxide using a 532 nm diode laser with a detection range in the low parts per billion range.

Detection of trace amounts of NO<sub>2</sub> using CW-CRDS

253rd National Meeting (2017)

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Detection of trace amounts of NO2 using CW-CRDS

Detection of trace amounts of NO₂ using CW-CRDS