Tm-Ho and Tm-Tb 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 C_DA, 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.