Thermosensitive Tm3+/Yb3+ co-doped oxyfluorotellurite glasses – spectroscopic and temperature sensor properties.

Oxyfluorotellurite (65- x)TeO 2 –20ZnF 2 –12PbO–3Nb 2 O 5 – x Tm 2 O 3 (x = 0.5, 2 and 5) and (65- x - y)TeO 2 –20ZnF 2 –12PbO–3Nb 2 O 5 – x Tm 2 O 3 – y Yb 2 O 3 (x = 0.5, y = 2 and x = 0.5, y = 5) glass systems were manufactured. Glass thermal stability was examined by means of differential thermal analysis (DTA) and some thermal stability criteria ΔT , H ' and S were determined. Absorption spectrum was utilized to prepare Judd-Ofelt (J-O) calculations and consequently oscillator strengths, intensity parameters Ω 2,4,6 , radiative transition probabilities, branching ratios and radiative lifetimes of luminescent levels were estimated. Emission spectra and luminescence decay curves were measured as a function of temperature in the 300–625 K range. Based on the upconversion luminescence of Tm3+ the optical temperature sensor qualities have been evaluated for Tm3+/Yb3+ co-doped sample. The fluorescence intensity ratio (FIR) between transitions 700 nm (Tm3+:3F 2,3 → 3H 6)/800 nm (Tm3+:3H 4 → 3H 6) for 975 nm excitation and 700 nm (Tm3+:3F 2,3 → 3H 6)/470 nm (Tm3+:1G 4 → 3H 6) for 803 nm excitation were determined and an adequate relative thermal sensitivity S was estimated. The significant value of relative thermal sensitivity 1.12 %K−1 was determined when NIR Yb3+ and Tm3+ emission bands were analyzed, however. Effective emission cross section was calculated for 3F 4 → 3H 6 potential laser transition of thulium around 1.9 μm in single-doped Tm3+ glass. Furthermore, effect of temperature on down-converted and up-converted thulium and ytterbium emission and on relaxation dynamic of involved excited states was studied in details. • Oyfluorotellurite glasses singly-doped and co-doped Tm3+ and Yb3+ were prepared. • Thermal and optical properties of tested materials were determined. • Thermal properties of glasses depend on the Tm3+/Yb3+ ions concentrations. • Investigated materials have advantageous properties for NIR optical gain. • TZPN glasses activated with RE3+ ions can be used in luminescence thermometry. [ABSTRACT FROM AUTHOR]