Fluorescence thermometer based on the photoluminescence intensity ratio in Tb doped phosphor materials

Terbium ion (Tb3+) doped silica glass (Tb:SiO2) and yttrium aluminum garnet crystals (Tb:YAG) have been fabricated for the applications in fiber-optic thermometers based on the temperature dependence of the photoluminescence (PL) spectrum. Several PL peaks at 490, 540, 585, 625 nm were observed from both Tb doped phosphors. In Tb:YAG crystal, the PL peaks were split into two or three small peaks due to the Stark effect. Temperature dependence of PL spectra from Tb:SiO2 glass and Tb:YAG crystal was evaluated over a temperature range from 300 to 1200 K. In the Tb:SiO2 glass, the peak PL intensity varied greatly with temperature. The shape of the PL spectrum from Tb:YAG crystal varied with temperature because the resolution of the split in the peak PL decreased with temperature. The intensity ratio between splitting PL peaks, therefore, varied with temperature. From these results, Tb:SiO2 glass and Tb:YAG crystals are considered to be a useful sensor head materials for high temperature measurement using temperature dependence of PL intensity. (C) 2005 Elsevier B.V. All rights reserved.