Tm3+–Ho3+ and Tm3+–Tb3+ energy transfer in tellurite glass

In Tm3+–Ho3+- and Tm3+–Tb3+-doped tellurite glasses, the IR fluorescence spectra and the lifetimes of the upper 3H4 and lower 3F4 lasing levels for 1.47 μm of Tm3+ were measured. The non-exponential decay is fitted using the Inokuti–Hirayama equation. The energy-transfer parameter CDA, critical ion distance R0, lifetime and non-radiative energy-transfer efficiency η between donor and acceptor ions are compared. The quenching mechanism has been explained. Both Ho3+ and Tb3+ ions reduce the lifetimes of the upper and lower lasing levels, with Tb3+ ions proving more efficient than the effects observed for Ho3+ ions. The optimised Tb2O3 concentration is about 1.0–1.5 wt%, which produced effective inversion and could be used for laser and amplifier applications.