Mid-infrared photo-luminescence and energy transfer around 2.8 μm from Dy3+/Tm3+ co-doped tellurite glass

Tellurite glasses co-doped with Dy3+ and Dy3+/Tm3+ have been synthesized. Emission around 2.8 μm is successfully obtained in present glass upon excitation of a conventional 808 nm laser diode. Judd-Ofelt intensity parameters and radiative properties of Dy3+ ions are calculated using the Judd-Ofelt theory. The luminescence characteristics and energy transfer mechanism are investigated and discussed. According to the absorption, fluorescence spectra and lifetime measurements, Tm3+ ions can effectively absorb excitation and transfer their energy to Dy3+ ions with high efficiency (up to 86.80%). Hence, the results demonstrate that Dy3+/Tm3+ co-doped tellurite glasses possessing excellent spectroscopic properties is a potential medium for mid-infrared laser.