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 comparing the absorption of infrared light in a gas cell at specific wavelengths. This task is performed by a non-dispersive spectral analyzer that operates at discrete wavelengths and has no moving parts (spectral retina). Several gases can be detected with the same detection principle, by simply selecting different signal channels. The spectral analyzer is made by coupling an array of integrated narrow band-pass optical filters to an array of PbSe detectors. Simultaneous detection of CO and SO2 with no cross-talk is demonstrated. A specific spectrally selective gas cell has been designed and fabricated. The new design greatly simplifies the fabrication process of the spectral analyzer and expands the range of operation towards longer wavelengths, useful for more sensitive detection of SO2 and NO2.