Measurement of nitric oxide spectral parameters: Considering the effects of CO and HO.

A continuous-wave quantum cascade laser (CW-QCL) based spectrometer is developed to investigate the high-resolution spectral parameters of nitric oxide (NO). Line strengths and nitrogen (N)-, carbon dioxide (CO)-, water vapor (HO)-, broadening coefficients for NO R(6.5) are measured. The spectral region ranging from 1989 cm to 1901 cm, which is suitable for the in situ laser sensing of trace NO, is investigated. Spectral parameters are determined by fitting absorption spectra with multi-peak Voigt profiles. The measured intensities are compared to the HITRAN2020 database to assess the performance of the system and a good agreement within ±5% is obtained for the established lines. The measurement results are useful for the design of a spectroscopic sensor for monitoring exhaled breath NO, vehicle exhaust, and industrial emissions.