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+:4I13/2 level was significantly reduced and the population inversion between the 4I11/2 and 4I13/2 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)