Nitrogen Oxides Optoelectronic Sensors Operating in Infrared Range of Wavelengths

Abstract

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 reectance 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 dierent mixtures of ArNO and ArN2O within the range from 100 ppb to 10 ppm was performed. The relative uncertainty of the results did not exceed the level of 13%.

A compact QCL based methane and nitrous oxide sensor for environmental and medical applications

“…Cavity enhanced absorption spectroscopy (CEAS) based N 2 O detection achieved a detection limit of 10 ppbv when targeting a N 2 O absorption line at 4.530 mm. 15 In this technique, two pairs of mirrors with high-reectivity (>99.9%) as well as critical optical alignments were required to achieve optimal performance of the CEAS based sensor system. Photoacoustic detection of N 2 O was recently reported using an 8 mm QCL and reached a detection limit of 80-100 ppbv, which is not sufficient for environmental monitoring.…”

Environmental Application of High Sensitive Gas Sensors with Tunable Diode Laser Absorption Spectroscopy

“…The near-infrared absorption band matches with the low loss window of optical fiber and is convenient for long-distance transmission and multipoint distributed detection by using fiber and fiber devices. Therefore, the absorption lines of selected CH 4 [46]. The parameters of three gases absorption lines are shown in Table 1.…”

“…With the globalization of economy and trade, environmental pollution is becoming more and more internationalized [1]. In order to control environmental pollution, great demands and tremendous efforts for new technology to detect hazard gases such as CH 4 , CO 2 , CO, HONO, H 2 S, and HCl have been performed. This would be beneficial for the implementation of global environmental protection policies for the reduction of gas pollution and for a general environmental management [2].…”

“…Several optical techniques have been developed to detect these hazard gases in the atmosphere [3][4][5][6][7][8][9][10]. Cavity-enhanced spectroscopy (CEAS) or cavity ring-down spectroscopy (CRDS) has been demonstrated to enable measurements of multiple gases with a low detection limit of sub-ppb [4][5][6]. However, these two technologies require critical optical alignment and regular cleaning of mirrors of the external cavity which affects continuous monitoring of atmospheric species in the field.…”

Atmospheric CH_4 and N_2O measurements near Greater Houston area landfills using a QCL-based QEPAS sensor system during DISCOVER-AQ 2013

“…During the last 10 years, different techniques, such as tunable diode laser absorption spectroscopy [5,6], photoacoustic absorption spectroscopy [7], and cavityenhanced absorption spectroscopy [8] were employed for CH 4 and N 2 O detection. In this work, we used the quartz-enhanced photoacoustic (QEPAS) technique to perform atmospheric measurements of these two targeted trace gas species.…”