It has been seen in a number of cases that glasses triply doped with certain rare-earth ions often results in increased intensity of the desired emission. But few results have been reported on the 2.7 emission in Er³⁺/Tm³⁺/Pr³⁺ triply doped glasses.

Researchers at Key Laboratory of Materials for High Power Laser -Shanghai Institute of Optics and Fines Mechanics (SIOM/China) obtained the 2.7 emission using 980 nm laser excitation in Er³⁺/Tm³⁺/Pr³⁺ triply doped ZrF₄–BaF₂–LaF₃–AlF₃–YF₃ glass, and investigated 2.7 emission characteristics and energy transfer .

They investigated the Er³⁺/Tm³⁺/Pr³⁺ triply doped fluoride glass with the chemical composition of 50ZrF₄–33BaF₂–17(LaF₃ + AlF₃ +YF₃) .They obtained the intense emission at 2.7 due to the efficient energy transfer between Er³⁺, Tm³⁺, and Pr³⁺ ions. With the introduction of Tm³⁺ and Pr³⁺ into the Er³⁺ doped system, the lifetime of the Er³⁺:4I_13/2 level was significantly reduced and the population inversion between the 4I_11/2 and 4I_13/2 levels becomed more possible. The present results suggested that the Er³⁺/Tm³⁺/Pr³⁺ ZBLAY glass can be considered as a promising material for a 2.7  laser.

Fig. The energy level diagram and energy transfer sketch map of the Er³⁺/Tm³⁺/Pr³⁺ triply doped ZBLAY glass when pumped at 980nm. (Image by SIOM)