Cao Yingchun, Sanchez Nancy P, Jiang Wenzhe, Griffin Robert J, Xie Feng, Hughes Lawrence C, Zah Chung-en, Tittel Frank K
Opt Express. 2015 Feb 9;23(3):2121-32. doi: 10.1364/OE.23.002121.
A continuous wave (CW) quantum cascade laser (QCL) based absorption sensor system was demonstrated and developed for simultaneous detection of atmospheric nitrous oxide (N(2)O), methane (CH(4)), and water vapor (H(2)O). A 7.73-µm CW QCL with its wavelength scanned over a spectral range of 1296.9-1297.6 cm(-1) was used to simultaneously target three neighboring strong absorption lines, N(2)O at 1297.05 cm(-1), CH(4) at 1297.486 cm(-1), and H(2)O at 1297.184 cm(-1). An astigmatic multipass Herriott cell with a 76-m path length was utilized for laser based gas absorption spectroscopy at an optimum pressure of 100 Torr. Wavelength modulation and second harmonic detection was employed for data processing. Minimum detection limits (MDLs) of 1.7 ppb for N(2)O, 8.5 ppb for CH(4), and 11 ppm for H(2)O were achieved with a 2-s integration time for individual gas detection. This single QCL based multi-gas detection system possesses applications in environmental monitoring and breath analysis.
展示并开发了一种基于连续波（CW）量子级联激光器（QCL）的吸收传感器系统，用于同时检测大气中的一氧化二氮（N₂O）、甲烷（CH₄）和水蒸气（H₂O）。使用一台波长在1296.9 - 1297.6 cm⁻¹光谱范围内扫描的7.73-µm连续波量子级联激光器，同时瞄准三条相邻的强吸收线，分别是1297.05 cm⁻¹处的N₂O、1297.486 cm⁻¹处的CH₄和1297.184 cm⁻¹处的H₂O。采用了一个光程长度为76米的像散多程赫里奥特池，在100托的最佳压力下用于基于激光的气体吸收光谱分析。数据处理采用波长调制和二次谐波检测。在单个气体检测的2秒积分时间下，实现了N₂O的最低检测限（MDL）为1.7 ppb、CH₄为8.5 ppb、H₂O为11 ppm。这种基于单个量子级联激光器的多气体检测系统在环境监测和呼吸分析中具有应用价值。
