Conclusions
The spectroscopic properties of Sm3 +-doped phosphate and fluorophosphate glasses have been studied through absorption, emission and decay curve analysis. The partial energy level structure of Sm3 + ions in these glasses has been obtained using the free-ion Hamiltonian model. The intensity parameters (Ω2, Ω4 and Ω6) have been evaluated using Judd–Ofelt theory. The Ω2 value is found to be larger which indicates that larger asymmetry at the Sm3 + ion site as well as stronger covalent nature of Smsingle bondO bond for the PKSASm10 glass compared to PKFSASm10 glass. 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, indicating that the 4G5/2 → 6H9/2 transition may be a potential lasing transition. The decay curves at higher concentrations exhibit non-exponential behavior and are well-fitted to Yokota and Tanimoto model indicating that the interaction for energy transfer between Sm3 + ions is of dipole–dipole type. 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 due to energy transfer processes among the Sm3 + ions.