INTEGRATED OPTICAL FILTERS FOR INFRARED ELECTROOPTICAL GAS SENSORS

A new system to improve greatly the characteristics of actual infrared (IR) sensors is proposed. The main characteristic of the system is its capability to integrate, on the same substrate, different thin-film optical filters with defined geometries for obtaining arrays of optical filters. This concept would make feasible multispectral integrated sensors or 'retinas' by hybrid or monolithic coupling of the filters with the detectors in the same or a very close substrate (focal plane). These retinas would possess spatial and spectral resolution capabilities. The development, among others, of integrated electrooptical sensors specially designed for monitoring pollutant gases is also possible. Experimental results from the work carried out up to now demonstrate the feasibility of the system proposed. Thin-film optical filters with adequate size, position and homogeneity have been obtained by combining different vacuum-evaporated multilayers on the same substrate.