Combining a difference-frequency source with an off-axis high-finesse cavity for trace-gas monitoring around 3 mu m
Authors: Malara P., Maddaloni P., Gagliardi G., De Natale P.
Autors Affiliation: CNR – Istituto Nazionale di Ottica Applicata and European Laboratory for Non-Linear Spectroscopy (LENS), Comprensorio “A. Olivetti”, Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
Abstract: High-sensitivity spectroscopy of methane around 3 mu m was carried out by means of a 5.5-mW cw difference-frequency generator in conjunction with a high finesse cavity in off-axis alignment. By cavity-output integration a minimum detectable absorption coefficient of 5.7(.)10(-9) cm(-1) Hz(-1/2) was achieved, which compares well with results already reported in the literature. Detection of methane in natural abundance was also performed in ambient air, for different values of total pressure, allowing direct concentration measurements via evaluation of the integrated absorbance of the spectra. In particular, at atmospheric pressure, a minimum detectable concentration of 850 parts per trillion by volume (pptv)(.)Hz(-1/2) was demonstrated. (c) 2006 Optical Society of America.
Journal/Review: OPTICS EXPRESS
Volume: 14 (3) Pages from: 1304 to: 1313
KeyWords: Absorption; Atmospheric pressure; Pressure effects; Spectroscopic analysis; Trace analysis, Ambient air; Cavity-output integration; Difference-frequency generator; Integrated absorbance, MethaneDOI: 10.1364/OE.14.001304Citations: 28data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2020-11-22References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here