Open AccessDifference-frequency-generator�??based spectrometer at 3 μm for high-sensitivity C2H2 and H2O detection
Author(s) -
Giulia Rusciano,
Giuseppe Pesce,
F. Pignatiello,
Antonio Sasso
Publication year - 2003
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.11.003010
Subject(s) - spectrometer , acetylene , materials science , water vapor , analytical chemistry (journal) , optics , spectroscopy , absorption spectroscopy , nitrogen , sensitivity (control systems) , absorption (acoustics) , nitrogen dioxide , impurity , chemistry , physics , organic chemistry , chromatography , quantum mechanics , electronic engineering , engineering
We detect acetylene and water-vapor lines by using a difference-frequency generator in the spectral region around 3 mm. Both C2H2 and H2O lines belong to fundamental vibrational bands and exhibit a line strength of the order of 10-20 cm/mol. Acetylene molecules were detected either by pure absorption or by first-derivative wavelength-modulation spectroscopy. The minimum detection sensitivity achieved for C2H2 in nitrogen was 4 ppb (parts in 109). Moreover, we discuss the effects of C2H2 pressure reduction in the presence of nitrogen in order to estimate systematic errors in the concentration measurements. Finally, we tested the accuracy of our spectrometer by detecting water vapor present as an impurity in a nitrogen cylinder at a nominal concentration of approximately 5 ppm.