Single-photon laser-induced fluorescence detection of nitric oxide at sub-parts per trillion mixing ratios | CU Experts

Abstract. We describe a newly developed single-photon laser-induced fluorescence sensor for measurements of nitric oxide (NO) in the atmosphere. Rapid tuning of a narrow-band laser on and off of a rotationally resolved NO spectral feature and detection of the red-shifted fluorescence provides for interference-free direct measurements of NO with a detection limit of 1 pptv for 1 second of integration, or 0.3 pptv for 10 seconds of integration. The instrument was deployed on the NASA DC-8 aircraft during the NASA FIREX-AQ experiment during July–September of 2019 and provided more than 140 hours of NO measurements over 22 flights, demonstrating the ability of this instrument to operate routinely and autonomously. Comparisons with a seasoned chemiluminescence sensor during FIREX-AQ in a variety of chemical environments provides validation and confidence of the accuracy of this technique.;

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