Tb3+/Yb3+ heavily-doped tellurite glasses with efficient green light emission

Without introducing concentration quenching phenomenon, a few wt.% of Tb3+ and Yb3+ ions were doped into a group of easily-fiberized tellurite glasses characterized by loose polyhedron structures and rich interstitial positions. Intense green upconversion emission from Tb3+ ions centered at 539 nm due to transition 5D4 → 7F5 was observed by direct excitation of Yb3+ ions with a laser diode at 976 nm. Optimizing the concentration ratio of Tb3+/Yb3+, a tellurite glass with a composition of 80TeO2–10ZnO–10Na2O (mol%) + 1.0 wt.% Tb2O3 + 3.0 wt.% Yb2O3 was found to present the highest green light intensity and therefore is especially suitable for efficient green fiber laser development.