Abstract: Method of manufacturing a sensitive single-layer system for optically detecting a concentration of an analyte, such as, for example, oxygen, the analyte being capable of investigation in liquid or gaseous aggregate condition or in a dissolved condition, by adsorption, luminescence or luminescence quenching of an indicator sensitive to the analyte, which is preferably permanently immobilized in the optical beam path. The sensitive single-layer system achieves a reproducible and extremely short response behavior. Indicators are adsorbed on a filler material and thereafter a mixture is produced with a matrix material permeable to the analyte to be detected. Then, under the action of pressure, the mixture is extruded onto a substrate, the layer thickness being formed in dependence on the applied pressure used. The applied sensitive layer is polymerized, polycondensed or hardened and the layer is also homogenized by swelling in a fluorescence indicator solution.