Energy transfer processes between Er3+ and Tm3+ were investigated examining the frequency upconversion emissions in a fluoroindate glass pumped at 790 nm. A 60-fold enhancement in the emission at ≈670 nm originating from Er3+ was observed when Tm3+ at concentration of 2% was introduced in a sample containing 2% of Er3+. The results are explained considering the influence of cross-relaxation processes between the active ions.
Bibliographical noteFunding Information:
This work was supported by the Brazilian Conselho Nacional de Desenvolvimento Cientı́fico e Tecnológico (CNPq) and Programa de Núcleos de Excelência (PRONEX). We also thank G.S. Maciel and N. Rakov for discussions and B.J.P. da Silva for polishing the samples.