Application of Quantum Cascade Lasers in Nitric Oxide and Nitrous Oxide Detection

Application of quantum cascade lasers in NO and $N_2O$ sensor is described. Cavity enhanced absorption spectroscopy was used for this purpose. The detection was performed at vibronic molecular transitions in spectral regions of 5.23-5.29 μm and 4.46-4.54 μm for NO and $N_2O$, respectively. In order to avoid interferences by the gases contained in atmosphere $(H_2O, CO_2)$ the lines of 5.263 μm for NO and 4.530 μm for $N_2O$ were selected. Our two channel sensor is designated for simultaneous detection of both compounds. Each channel consists of single mode quantum cascade laser, optical cavity, and a photodetection module. The lasers were precisely tuned to the wavelength of interest. Optical cavities were built with spherical mirrors of high reflectance. The signals from the cavities outputs were registered with specially developed low noise detection modules