Colorimetric gas sensors based on optical waveguides made on plastic foil

We report on the realization of a low-cost polymeric optical waveguide made on a plastic foil and used for colorimetric gas detection. Low-temperature processes have been used for the realization of polymeric micro-mirrors and the depositions of the chemochromic reagent on PET foil. The planar waveguide configuration aims at improving the transducer sensitivity and simplifies its fabrication. Indeed, the device is currently produced by standard microfabrication techniques but its configuration and the materials involved make the sensor compatible with large scale and low-cost fabrication techniques. The operation of the optical transducer was applied to a colorimetric gas sensor and validated for the detection of ammonia.