Optical sensor for detection of chemical species

摘要

PCT No. PCT/EP94/01768 Sec. 371 Date Nov. 7, 1995 Sec. 102(e) Date Nov. 7, 1995 PCT Filed May 31, 1994 PCT Pub. No. WO94/28395 PCT Pub. Date Dec. 8, 1994Disclosed and claimed is an optical sensor for the detection of chemical species. The optical sensor includes an optical waveguide having a guiding thin film. The thickness of the refrative index of the guiding thin film changes due to adsorption or absorption of the chemical species or reaction of the chemical species with the guiding thin film. The thickness of the guiding thin film is above the cutoff thickness in the presence of gaseous or liquid chemical species to be detected. And, the thickness of the guiding thin film is below the cutoff thickness in the absence of such chemical species.