A compact, single-pass and low-power-consumption methane sensing system is presented and its sensitivity is investigated for a set of reference cells with pressures of 7.4, 74 and 740 Torr and the same methane concentration of 1351 ppm. A single-mode GaSb-based continuous-wave (CW) distributed feedback (DFB) tunable diode laser at 3270 nm and wavelength modulation spectroscopy were employed to collect 2f spectra in the ν₃,R₃ band of ¹²CH₄. A modulated Voigt line profile model was used to fit the collected 2f spectra. The best detectivity of 4 ppbm is obtained for the highest pressure cell using an Allan-Werle variance analysis.

Date Published: 31 January 2020
PDF: 8 pages
Proc. SPIE 11288, Quantum Sensing and Nano Electronics and Photonics XVII, 1128822 (31 January 2020); doi: 10.1117/12.2545014

Published in SPIE Proceedings Vol. 11288:
Quantum Sensing and Nano Electronics and Photonics XVII
Manijeh Razeghi; Jay S. Lewis; Giti A. Khodaparast; Pedram Khalili, Editor(s)