MULTISPECTRAL INTERFERENCE FILTERS AND THEIR APPLICATION TO THE DESIGN OF COMPACT NONDISPERSIVE INFRARED GAS ANALYZERS FOR POLLUTION-CONTROL

The integration process of different thin-film interference filters on a unique substrate to give multispectral filter arrays has been studied. Filter arrays properly combined with detector arrays would permit the obtention of multispectral integrated sensors or retinas with spatial and spectral resolution, possibly in the focal plane of a staring sensor. In this work experimental results related to the planar integration of different multilayers onto the same substrate are described. Special attention is devoted to the study of the stability of multilayer properties and their relation to the development and photolithographic process parameters. The application of infrared filter arrays to the development of compact non-dispersive infrared sensors with no moving parts for gas analysers is also discussed.