Fluorescence characteristics of Nd3+ doped multicomponent fluoro-phosphate glasses for potential solid-state laser applications

Abstract

The multicomponent fluoro-phosphate glasses of the type, 49.5P2O5–10AlF3–10BaF2–10SrF2–10PbO–10M (M=Li2O, Na2O, K2O, ZnO and Bi2O3) doped with 0.5mol% neodymium were prepared by melt quenching technique. Their structures were characterized by the X-ray diffraction with SEM analysis, Fourier transform infrared (FTIR), Raman spectroscopy and 31P and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) techniques. XPS spectra were studied to know the bridging and non-bridging oxygen groups. X-ray absorption near edge spectroscopy (XANES) was used to study the electronic structure of neodymium in the host glass matrices. The Judd–Ofelt parameters (J–O) (Ω2, Ω4 and Ω6) were evaluated from the intensities of the absorption bands through optical absorption spectra. Further, J–O parameters have been used to calculate various radiative properties like probabilities of radiative transitions, radiative lifetimes and branching ratios for different fluoro-phosphate glasses. The luminescence kinetics from the excited neodymium levels have been studied upon selective excitation through photoluminescence measurements. Neodymium ion emits two near infrared laser emissions: 4F3/2→4I11/2 at 1.06μm and another one 4F3/2→4I13/2 at 1.32μm. The major intensity is observed for 1.06μm for the prepared fluoro-phosphate glasses. The lifetimes of these levels have been experimentally determined through decay profile studies. The above results suggest that the prepared lithium fluoro-phosphate glass system could be a suitable candidate for using it as 1.06μm laser source in the near infrared region of spectrum.