Influence of BaX2 (X = Cl, F) and Er2O3 concentration on the physical and optical properties of barium borate glasses

Er3+ ions doped oxyhalide barium borate glasses were prepared by means of conventional melt quenching technique. In the studied glass system, besides the Er3+ doping, barium oxide was partially replaced by BaF2 and/or BaCl2. The amorphous nature of as-prepared glasses was confirmed by X-ray diffraction patterns. The effects of the compositional changes were investigated through spectroscopic techniques such as optical absorption, emission and decay lifetime. It was found that the luminescence and decay lifetime of Er3+: I-4(13/2) -> I-4(15/2) transition are affected by both Er3+ doping and halide insertions. By applying the Judd-Ofelt (JO) theory, the JO intensity parameters (Omega(t), t = 2, 4, and 6) were calculated, and the trend Omega(2) > Omega(4) > Omega(6) was found, which is in accordance with previous studies. Optical properties such as electric and magnetic dipole transition probabilities, fluorescence branching ratios, integrated emission cross sections and radiative lifetimes were also obtained and discussed for many excited states of Er(3+ )ions. The lifetime of the I-4(13/2) excited level was measured and compared with the calculated one.