Highly sensitive and real-simultaneous CH4/C2H2 dual-gas LITES sensor based on Lissajous pattern multi-pass cell

• Published in: Opto-Electronic Science Vol. 3; no. 11; pp. 1 - 11
• Main Authors: Haiyue Sun, Ying He, Shunda Qiao, Yahui Liu, Yufei Ma
• Format: Journal Article
• Language: English
• Published: National Key Laboratory of Laser Spatial Information,Harbin Institute of Technology,Harbin 150000,China 01.11.2024; Editorial Office of Opto-Electronic Journals, Institute of Optics and Electronics, CAS, China
• Subjects: dual-gas sensing; light-induced thermoelectric spectroscopy; lissajous space-division multiplexed; multi-pass cell; quartz tuning fork; dual-gas sensing; light-induced thermoelectric spectroscopy; Lissajous space-division multiplexed; multi-pass cell; quartz tuning fork
• ISSN: 2097-0382
• DOI: 10.29026/oes.2024.240013

In this paper,a novel highly sensitive methane(CH4)and acetylene(C2H2)dual-gas light-induced thermoelectric spec-troscopy(LITES)sensor based on Lissajous space-division multiplexed(LSDM)technology and trapezoidal-head quartz tuning fork(QTF)detector was reported for the first time.A theoretical LSDM model was established on the basis of three-mirror astigmatic multi-pass cell(MPC)and it was used to design a pair of Lissajous spot patterns with optical path length to volume ratios(OPL/Vs)of 13.5 cm?2 and 13.3 cm?2,respectively.Two self-designed trapezoidal-head QTFs with low resonant frequencies of less than 10 k Hz and quality factor of～12000 were adopted to enhance the detection ability.Two kinds of fiber amplifier,erbium doped fiber amplifier(EDFA)and Raman fiber amplifier(RFA),were com-bined to amplify the output power of two diode lasers to improve the excitation strength.After optimization,minimum de-tection limit(MDL)of 268.8 ppb and 91.4 ppb for real-simultaneous CH4 and C2H2 sensing were obtained,respectively.When the integration time of the system were 150 s and 100 s,the MDLs could be improved to 54.8 ppb and 26.1 ppb,accordingly.Further improvement methods for such sensor were discussed.