Optics and Precision Engineering, Volume. 32, Issue 23, 3424(2024)
Sensitivity improvement of NO gas detection based on mid-infrared TDLAS
Accurate detection of nitric oxide (NO) is crucial for applications in environmental, biomedical, and other fields. NO demonstrates strong absorption in the mid-infrared wavelength range, enabling high-sensitivity detection using tunable diode laser absorption spectroscopy (TDLAS) with a mid-infrared quantum cascade laser as the light source. This study develops a three-stage thermoelectric cooler (TEC)-based temperature control structure, introduces a concentration inversion model, and enhances detection sensitivity through optimized laser temperature stability and gas concentration inversion. Experimental results reveal rapid stabilization of laser temperature at room temperature with a stability of 0.003 ℃. The proposed model outperforms the 2f/1f model under identical conditions. Utilizing the signal's peak-to-peak value for concentration inversion over a 30 m optical path and with three-stage laser temperature control, the system achieves an NO concentration measurement linearity of 0.997 5 and a detection limit of 37.5×10-9 within a 0-500×10-6 range. By optimizing both laser temperature control and the inversion model, the NO detection sensitivity is improved by two orders of magnitude.
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Wenjin XING, Runhao LI, Yunfeng BI. Sensitivity improvement of NO gas detection based on mid-infrared TDLAS[J]. Optics and Precision Engineering, 2024, 32(23): 3424
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Received: Jul. 11, 2024
Accepted: --
Published Online: Mar. 10, 2025
The Author Email: BI Yunfeng (byf@sdu.edu.cn)