Er3+,Yb3+-doped oxyfluorotellurite glasses-Impact of temperature on spectroscopic properties and optical sensor qualities

Oxyfluorotellurite glasses co-doped with erbium (0.5%) and ytterbium (2%, 5%) were manufactured from high purity reagents at 840 degrees C in air. Differential thermal analysis was used to estimate the temperatures of glass transition and glass crystallization of 2% and 5%Yb co-doped glasses. The effect of Yb(3+ )co-doping on relaxation dynamics of erbium excited states was demonstrated by the means of excitation, emission and fluorescence lifetime spectroscopy. Up-conversion luminescence spectra were studied in a function of temperature in the 295-675 K range, yielding information on thermal quenching of the emission and a temperature sensing model based on H-2 (11/2)-I-4(15/2) to S-4(3/2)-(4)I(15/2 )erbium fluorescence intensity ratio. Application potential of the investigated material in optical sensor thermometry was evaluated. Maximum absolute and relative sensitivities were established at 6.45 x 10(-3) K-1 at T = 675 K and 0.46 %K-1 at T = 400 K, respectively.