Consequences of TiO2 doping on the optical properties of porous silica layers coated on silica optical fibers

TiO2–SiO2 sol–gel hybrid films and their sensitivity to gaseous toluene

“…Angular distributions have been used for the estimation of complex refractive indices of films applied onto optical fibers by using a model published elsewhere [5,6]. An example of results of this modeling can be seen from Fig.…”

“…These parameters influence angular distributions of fibers with the applied sensing layers. This influence can be explained by a ray-optic model [5,6]. In Fig.…”

“…Optical characteristics of the prepared xerogel layers applied on optical fibers and their sensitivity to toluene were determined by using an experimental set-up shown in Fig. 1 [5].…”

“…However, this approach was irreversible [4]. Detection limits for toluene in air ranged from 150 to 700 lg/l were achieved with detection fibers which employed refractive-index changes of xerogel detection membranes applied on polymer-clad silica (PCS) fibers [5][6][7]. The membranes were prepared of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), phenyltriethoxysilane (PhTES) or titaniumisopropoxide (TiIP).…”

“…Excitation of the fibers with the membranes by an inclined collimated beam was used for increasing the fraction of power transmitted in the membrane. Theoretical model of experimental results was carried out which resulted into estimations of optical properties of the membranes and into values on interaction parameters [5,6].…”