The effect of La2O3 in Tm3+-doped germanate-tellurite glasses for ~2 μm emission

A germanate-tellurite glass (GeO2-TeO₂-K₂O-Nb₂O₅-La₂O₃) with thulium doping has been investigated for application as a laser material around 2.0 μm regions. Under the 808 nm laser diode pumped, intense 1.8 μm emission is obtained. Based on the absorption spectra, radiative properties are predicted using Judd-Ofelt theory. The maximum value of emission cross-section of Tm(3+) around 1.8 μm can reach 1.46 × 10(-20) cm(2), which indicated that the germanate-tellurite glass may provide high gain as a good medium for efficient 1.8 μm laser system.