Red emission, upconversion and intensity parameters of erbium oxide doped tellurite glass for laser glass

This work presents the effect of erbium oxide in tellurite glass on the intensity parameters, emission and upconversion to be used as laser glass. We select 0.04 mol fraction of erbium oxide in tellurite glass as it gives the optimum results for glass stability, luminescence and intensity parameters. The structural arrangement of glass matrices was revealed by XRD analysis. The amorphous structural arrangement was found and there was no crystalline structure existed in the glass matrix. The FTIR analysis revealed the existence of TeO3 non-bridging oxygen which has important role in the shifting of the optical parameters. The Judd–Ofelt analysis (intensity parameters, Ωλ = 2, 4, 6) were studied by applying nine transition states obtained from UV–Vis-NIR absorption spectrum which were 4G11/2 + 2H9/2 + 4F5/2 + 4F7/2 + 2H11/2 + 4S3/2 + 4F9/2 + 4I9/2 + 4I11/2. The obtained results for the intensity parameters were in accordance by the following trends Ω2 > Ω4 > Ω6. A broad red emission at 648 nm was found with excitation state of 380 nm. Four emission peaks were found from upconversion emission spectrum as follows; 381 nm, 420 nm, 466 nm and 560 nm which correspond to 4G11/2 → 4I15/2, 4F3/2 → 4I15/2, 4F7/2 → 4I15/2 and 4S3/2 → 4I15/2. The prominent emission for upconversion was 560 nm which produce yellow emission. Based on these results, erbium doped boro-tellurite glass is capable to be utilized as red, blue and green glass lasers. The absorption and emission cross sections and optical gain factor have been carried out by using Mc-Cumber theory.