Intense 27 µm emission of Er^3+-doped water-free fluorotellurite glasses

By physical and chemical dehydration techniques, a group of Er3+-doped water-free fluorotellurite glasses with a composition of 60TeO2–30ZnF2–10NaF(TZNF60,mol%)+x Er2O3(wt%,x=0∼1.5) were fabricated. Under 978 nm excitation, the I11/24→I13/24 emission of Er3+ ions in TZNF60-glass was investigated: τf is of 1.07∼1.93 ms and emission bandwidth is about 163 nm at 2.71 µm, which benefits from the absence of OH groups and the decreased phonon energy with the addition of fluorides. In contrast, 1.25Er-TZNF60 glass is proposed to be a promising material for mid-infrared fiber lasers at around 2.7 µm.