Optische Dünnschicht-Gassensoren - Refraktions- und Absorptionseffekte

: Brandenburg, A.; Edelhäuser, R.; Hutter, F.

Abstract
Integrated optical devices are proposed for gas sensing. By means of this planar technology, complex optical structures can be realized as compact and very stable devices, demanding no further optical adjustment. The possibility of cost-efficient fabrication is given. The gas to be measured is absorbed by a thin sensitive film, which is deposited on a planar optical structure. For our investigations, organically modified silicates have been used as sensitive films. The sensitivity of these films is determined by incorporating different indicator dyes or functional groups into these films. The films may change either refractive index or optical absorption coefficient with gas absorption. The optical properties of the films are probed by the guided light via the evanescent wave.