By the use of commercial A1GaAs diode lasers and short radiation path-length, frequency modulation (FM) absorption spectroscopy has been performed in the near infrared to study the overtone absorption bands of molecules interesting as environmental sensing tracers. Our measurements concern water vapor resonances around 820 nm, methane around 780 nm and 860 nm, and ammonia around 790 nm. Pressure broadening coefficients have been extracted by using different buffer gases like air, N2 , He, and by varying their pressure between 10 and 760 Torr. A x2 fitting of the absorption line shapes has been used for this purpose by the aid of a simple fitting function. Finally an estimation of the sensitivity of the technique is made.

Date Published: 24 September 1993
PDF: 12 pages
Proc. SPIE 1711, High-Performance Optical Spectrometry, (24 September 1993); doi: 10.1117/12.155665

Published in SPIE Proceedings Vol. 1711:
High-Performance Optical Spectrometry
Maksymilian Pluta; Aleksandra Kopystynska; Mariusz Szyjer, Editor(s)