Effects of WO_3 Contents on the Thermal and Spectroscopic Properties of Tm~(3+)-doped TeO_2-WO_3-La_2O_3 Glasses

Tungsten-lanthanum-tellurite(TWL) glasses with the molar composition(90-x)TeO2-xWO3-9La2O3-1Tm2O3(x=10,20,30(mol%)) were prepared.Effects of WO3 contents on the thermal stability and spectroscopic properties of Tm3+ doped TWL glasses were studied.It is found that the thermal stability of TWL glasses is improved with the increasing WO3 contents.For the glass with 30mol% WO3,the glass transition temperature(Tg) is 457℃,while onset crystallization temperature(Tx) is not observed in DTA curve,and the thermal expansion coefficient of the glass decreases to 1.224×10-5/℃(30-300℃).The maximum phonon energy of the glasses shows the dependence on the host composition.The spectroscopic intensity parameters(Ωt t=2,4,6),radiative transition rates,radiative lifetimes,and branching ratios are calculated by Judd-Ofelt theory.The emission cross-section of Tm3+: 3F4→3H6 transition is calculated by McCu-mber theory.The maximum emission cross-section of Tm3+ in 60TeO2-30WO3-9La2O3-1Tm2O3 glass is 9.6×10-21cm2.Evaluated from the thermal and spectroscopic properties,60TeO2-30WO3-10La2O3 glass is a promising host material for ~2.0μm laser.