Spectroscopic properties of Sm3 + ions in phosphate and fluorophosphate glasses

Spectroscopic properties of Sm3 +-doped phosphate and fluorophosphate glasses of the composition (60 − x / 2) P2O5 + 15 K2O + (15 − x / 2) SrO + 10 Al2O3 + x Sm2O3 (PKSASm) and (54 − x / 2) P2O5 + 14 K2O + 10 KF + (13 − x / 2) SrO + 9 Al2O3 + x Sm2O3 (PKFSASm), where x = 0.1, 0.5, 1.0, 2.0, 4.0 and 6.0 mol%, have been investigated. The oscillator strengths and the intensity parameters (Ω2, Ω4 and Ω6) have been determined using the Judd–Oflet theory, which in turn is used to predict the radiative transition probability (AR), radiative lifetime (τR) and branching ratios for the fluorescent 4G5/2 level. The higher stimulated emission cross-sections, 12.27 × 10− 22 and 14.12 × 10− 22 cm2 have been observed for the 4G5/2 → 6H9/2 transition of PKSASm10 and PKFSASm10, respectively. The non-exponential nature of the decay curves of the 4G5/2 level increases with increase in Sm3 + ion concentration accompanied by decrease in lifetime. The non-exponential decay curves have been best fitted to the generalized Yokota–Tanimoto model indicating that the energy transfer among optically active ions is through dipole–dipole interaction.