We report on the measurement of the NO₂ concentration in ambient air using a highly sensitive trace gas detector based on a simplified design that uses a multi-mode diode laser and cavity enhanced multiple line integrated absorption spectroscopy. The broad frequency range of the laser covers a large number of absorption lines of NO₂ and excites a large number of cavity modes. The off-axis cavity arrangement reduces the detector’s susceptibility to vibration. The detector was calibrated using known concentrations of NO₂ in zero air and used to measure the concentration of NO₂ in ambient air in our laboratory. A sensitivity of 75 ppt was achieved.

Date Published: 13 May 2015
PDF: 10 pages
Proc. SPIE 9486, Advanced Environmental, Chemical, and Biological Sensing Technologies XII, 94860H (13 May 2015); doi: 10.1117/12.2179501

Published in SPIE Proceedings Vol. 9486:
Advanced Environmental, Chemical, and Biological Sensing Technologies XII
Tuan Vo-Dinh; Robert A. Lieberman; Günter G. Gauglitz, Editor(s)