Enhanced 2.7 μm emission of Er3+-doped low hydroxyl fluoroaluminate-tellurite glass

New fluoroaluminate-tellurite glasses with high thermal stability were fabricated through introducing TeO2 into the fluoroaluminate glass (AlF3-YF3-CaF2-BaF2-SrF2-MgF2). 2.7 μm emission properties were investigated through the measured absorption and emission spectra. For the first time it was found that the OH− absorption coefficient at 2.84 μm was reduced to 1/15 for the fluoride system by introducing TeO2. X-ray diffraction showed that the sample without TeO2 composition showed some crystallization phases when the glass was reheated. However, the addition of TeO2 changed the crystallization mechanism and improved the glass forming ability of the fluoroaluminate glass. Enhanced 2.7 μm emission was observed in the fluoroaluminate-tellurite glass under 980 nm excitation and the calculated spontaneous transition probability (А), branching ratio (β) and emission cross section (σem) were larger than some reported values. These results indicate that this kind of fluoroaluminate-tellurite glass has potential applications as host material for 2.7 μm lasers.