SPECTRALLY SELECTIVE GAS CELL FOR ELECTROOPTICAL INFRARED COMPACT MULTIGAS SENSOR

Progress in a new electrooptical compact gas sensor system is reported . The sensor measures pollutant concentrations in the atmosphere by co mparing the absorption of infrared light in a gas cell at specific wav elengths. This task is performed by a non-dispersive spectral analyzer that operates at discrete wavelengths and has no moving parts (spectr al retina). Several gases can be detected with the same detection prin ciple, by simply selecting different signal channels. The spectral ana lyzer is made by coupling an array of integrated narrow band-pass opti cal filters to an array of PbSe detectors. Simultaneous detection of C O and SO2 with no cross-talk is demonstrated. A specific spectrally se lective gas cell has been designed and fabricated. The new design grea tly simplifies the fabrication process of the spectral analyzer and ex pands the range of operation towards longer wavelengths, useful for mo re sensitive detection of SO2 and NO2.