It has been found that thin layers of aerogels applied by the sol-gel method on silica optical fibers change their optical properties due to the interaction with gases such as hydrocarbons. This paper deals with modification of the sensitivity and selectivity to vapors of hydrocarbons and chlorinated hydrocarbons of siloxane aerogel layers based on their doping with TiOTi chains and/or immobilizing in them Cu-ephedrine and Cu-phthalocyanine. The sensing fibers were prepared by the sol-gel application of porous siloxane and doped-siloxane layers on bare cores of PCS fibers. By using the excitation of the fiber with inclined laser beams it is experimentally shown that there are positive or negative changes of the output optical power from the fibers due to bringing the prepared layers into contact with vapors of aliphatic, aromatic and chlorinated hydrocarbons in nitrogen. These effects may be related to a difference between the refractive index of the layer and refractive index of liquid hydrocarbon or hydrocarbon its derivative. It is shown experimentally that doping porous siloxane layers with copper complexes changes their refractive index and optical losses changing thus their sensitivity and selectivity to hydrocarbons and hydrocarbon derivatives.
展开▼
