Sensitizing effect of Ho3+ on the Er3+: 2.7 mu m-emission in fluoride glass

The fluorescence properties of 2.7 pm emission and energy transfer mechanism of Ho3+/Er3+ co-doped fluoride glass (ZBYA) have been investigated in the present paper. Ho3+ strengthens the Er3+: 2.7 lam emission in the ZBYA glasses due to the energy transfer from Er3+ to Ho3+, while the 1.5 iirn emission decreases dramatically. The optimized concentration ratio of Er3+ to Ho3+ is found to be 1:1 in our glass system. The absorption and emission spectra are tested and the sample possesses large emission cross section (16.5 x 10(-2) cm(2)) around 2.7 jim along with larger radiative transition probability (25.11 S-1) on the basis of Judd-Ofelt and Fuchtbauer-Ladenburg theories. Additionally, the energy transfer microparameters are calculated using Forster-Dexter theory and the result shows the energy transfer coefficient of Er3+:4I(13/2) -> Ho3+:I-5(7) is 24 times larger than that of Er3+:4I(11/2) -> Ho3+:I-5(6). Our results show that Er: 2.7 gm emission can be sensitized by Ho3+ efficiently, and this Er3+/Ho3+-codoped fluoride glasses might have potential application in mid-infrared lasers. (C) 2013 Elsevier B.V. All rights reserved