Er3+:Yb3+ codoped lead fluoroindogallate glasses for mid infrared and upconversion applications

In this work, two sets of lead fluoroindogallate glasses were studied with the aim of using them as active media for laser devices at the mid infrared (similar to 2.8 mu m) and visible (similar to 0.54 mu m) regions. The infrared and upconverted emissions of Er3+ in single and Er3+:Yb3+ codoped samples were analyzed, and it was observed that the best set of samples for 2.8 mu m emission was the single doped one, and that as the upconversion (anti-Stokes luminescence) increased as a function of Yb3+ concentration, the infrared emission decreased in the same manner. The results suggest that the codoping with Yb3+ favors only the upconversion processes which depopulate the I-4(11/2) level, reducing the 2.8 mm emission intensity. On the other hand, the Yb3+ codoping will certainly increase the efficiency of an upconversion based device. Quantum efficiencies of infrared emissions and radiative lifetimes were calculated by using the Judd-Ofelt approximation. Er3+-Er3+ and Er3+-Yb3+ energy transfer efficiencies were calculated using the measured lifetimes of the levels involved in the energy transfer processes. (C) 1999 American Institute of Physics. [S0021-8979(99)03105-9].