. . "For the sensor comprising a donor layer (D) applied to a solid substrate and a layer (A) which contains a coupling component (K) and which, after reaction with an analyte, becomes an acceptor layer, the following may be used as the solid substrate: glass, quartz, semiconductor materials, such as germanium, GaAs or silicon, Li niobate, zinc selenide, porcelain, metallic layers, optofibers, waveguid" . .