Nitrogen Oxides Optoelectronic Sensors Operating in Infrared Range of Wavelengths

Investigation of nitric oxide and nitrous oxide optoelectronic sensors is described. The detection of both components was done by measurement of absorption that occurs due to transition between vibronic molecular transitions. The improvement of the sensitivity was achieved due to application of cavity enhanced absorption spectroscopy. Two optical cavities (each one for each gas) built of high re ectance spherical mirrors were used. While the spectra of observed transitions are situated in mid-infrared range, two single mode quantum cascade lasers were applied. Their narrow emission lines were precisely tuned to the absorption lines of both investigated gases. The measurement of di erent mixtures of Ar NO and Ar N2O within the range from 100 ppb to 10 ppm was performed. The relative uncertainty of the results did not exceed the level of 13%.