Title :
Difference-frequency-based laser spectrometer for trace CH4 detection
Author :
Chen, Dong ; Liu, Wenqing ; Zhang, Yujun
Author_Institution :
Sch. of Instrum. Sci. & Opto-Electron. Eng., Hefei Univ. of Technol., Hefei, China
Abstract :
A laser spectrometer based on difference-frequency generation in periodically poled LiNbO3 (PPLN) has been developed. The mid-infrared laser source was pumped by complementally two commercial narrow linewidth diode laser, to produce about 1μw of output power in the tuning region from 3.2μm to 3.7μm. The spectrometer was used for trace CH4 measurement, a CH4 absorption line at 3028.751 cm-1 of v3 band was chosen as this line is relatively free of interference by other gas species. The selected absorption line was verified using a single-pass cell detection. The detection sensitivity is estimated to be 0.8ppm for 10cm optical path length at atmospheric pressure, and is limited mainly by the etalon noise of optical surfaces.
Keywords :
atmospheric pressure; chemical variables measurement; gas sensors; infrared spectrometers; infrared spectroscopy; laser tuning; light interferometers; lithium compounds; measurement by laser beam; optical frequency conversion; organic compounds; semiconductor lasers; LiNbO3; atmospheric pressure; detection sensitivity; difference frequency-based laser spectrometer; difference-frequency generation; etalon noise; methane absorption line; mid-infrared laser source; narrow linewidth diode laser; optical path length; optical surfaces; single-pass cell detection; trace methane detection; trace methane measurement; Laboratories; Optical diffraction; Optical filters; Optical pumping; Pump lasers; Reflection; Difference-frequency generation (DFG); Methane (CH4); Mid-infrared laser spectroscopy; spectrometer;
Conference_Titel :
Electronics and Optoelectronics (ICEOE), 2011 International Conference on
Conference_Location :
Dalian
Print_ISBN :
978-1-61284-275-2
DOI :
10.1109/ICEOE.2011.6013289
