2.7 μm fluorescence and energy transfer in Er3+ doped germanosilicate glasses

2.7 μm fluorescence has been achieved for the first time in Er3+ doped novel germanosilicate glasses. Thermal stability, spectroscopic properties and energy transfer mechanism have been investigated in detail. Moreover, the spontaneous transition probability (Arad) and emission cross section of samples were calculated and analyzed. The prepared Er3+ doped germanosilicate glasses possessing excellent thermal stability, high Arad (33.75 s−1) and emission cross section of 2.7 μm (1.90 × 10−20 cm2) provide a new material for the realization of mid-infrared fiber lasers.