Applications of Supercontinuum Sources for Trace Gas Sensing

Abstract

Abstract Optical absorption spectroscopy is a widely used method for gas detection, with many different applications in physics, chemistry, biology, environmental science, etc. Recent developments in mid‐infrared supercontinuum sources have opened up new possibilities for trace gas detection in these research fields. Supercontinuum sources have a wide spectral range (spectral coverage of a lamp), a high light intensity, and a high spatial coherence (directionality of a laser). The wide coverage enables to detect gases in complex gas mixtures, while the directionality allows a long path length through the gas sample, thereby improving the sensitivity for specific gases. After a short historical overview and background on the generation of supercontinuum light, attention is focused on the combination of supercontinuum sources, gas cells, and spectroscopic detection systems, to achieve an optimal detection limit and selectivity for gasses. The main methods for improving the signal‐to‐noise ratio ( SNR ) and detection sensitivity of gases are discussed. Applications are described with examples of the detection of gaseous pollutants in the atmosphere, postharvest physiology, and plasmas analysis.