Cooperative downconversion and near-infrared luminescence of Tb~(3+)/Yb~(3+) co-doped tellurite glass

摘要

The different concentration of Tb~(3+)/Yb~(3+) co-doped tellurite glasses were prepared by high-temperature melting-quenching method. The near-infrared (NIR) luminescence of co-doped samples upon the excitation of Tb~(3+) ions with a green visible photon at 484 nm was investigated, and two NIR photons could be emitted by Yb~(3+) (~2F_(5/2) -> ~2F_(7/2)) through cooperative energy transfer from Tb~(3+) to two Yb~(3+) ions. On the other hand, the Yb~(3+) co-doped concentration dependence on the visible and NIR emissions, decay lifetimes and quantum efficiencies from the downconversion have been studied. The NIR quantum efficiency achieved 172% before the concentration quenching threshold.