A laser absorption spectrometer is described which uses a tunable diode laser and a 1-m multipass White cell to detect NO2 in air with a sensitivity of better than 100 ppt. The modulation techniques employed to achieve this sensitivity are described in detail, and the noise mechanisms, which currently limit the detectable absorption coefficients to ≳10−7 m−1, are examined.
© 1980 Optical Society of America
Original Manuscript: May 15, 1980
Published: October 1, 1980
J. Reid, M. El-Sherbiny, B. K. Garside, and E. A. Ballik, "Sensitivity limits of a tunable diode laser spectrometer, with application to the detection of NO2 at the 100-ppt level," Appl. Opt. 19, 3349-3354 (1980)