Highly-sensitive NO, NO<sub><bold>2</bold></sub>, and NH<sub><bold>3</bold></sub> measurements with an open-multipass cell based on mid-infrared wavelength modulation spectroscopy

Highly-sensitive NO, NO₂, and NH₃ measurements with an open-multipass cell based on mid-infrared wavelength modulation spectroscopy

Chen Xiang^{1, 2}, Yang Chen-Guang¹, Hu Mai¹, Shen Jian-Kang³, Niu Er-Chao³, Xu Zhen-Yu¹, Fan Xue-Li¹, Wei Min^{1, 2}, Yao Lu¹, He Ya-Bai¹, Liu Jian-Guo¹, Kan Rui-Feng^{1, †}

(color online) Schematic diagram of an open-path instrument for atmospheric gas sensing, based on the wavelength modulation spectroscopy technique and mid-infrared quantum cascade lasers.