Spectroscopic determination of nitrogen oxide content in measurement chamber

摘要

A conventional frequency modulation spectroscopy method is used to modulate a narrow band light source so that two lateral lines occur in the emission spectrum of the light source. One line coincides with the absorption line of a harmonic of a nitrogen oxide molecule.The modulated light from the source is used as the measurement light for the measurement chamber. Light is passed through the measurement chamber along several different sight lines and is separately detected. A position resolution is achieved by combining the results of the separate detections.