Erbium doped sodium magnesium boro-tellurite glass: Stability and Judd-Ofelt analysis

Understanding the influence of rare earth ions in improving the optical properties of glasses are important in order to extend in advanced application. The behavior of series of Er3+ (1.0-2.0 mol %) doped B2O3-TeO2-MgO-Na2O glasses synthesized by conventional melt-quenching technique are explored. X-ray diffraction (XRD) pattern confirms the amorphous nature of the prepared glass sample. The DTA data asserts that the addition of Er3+ increased the thermal stability from 142 to 207 °C. The UV-VIS-NIR spectra reveal ten absorption bands centered at 4G11/2, 2H9/2, 4F5/2,4F7/2, 2H11/2, 4S3/2,4F9/2, 4I9/2, 4I11/2 and 4I13/2 from ground state of 4I15/2. The Judd-Ofelt Ω2 parameter values gradually decreases with the increase of erbium ions concentration from 0.5 to 2 mol %. From the Judd-Ofelt parameters (Ωt), transition probabilities (A), branching ratios (βR) of various transitions and their radiative lifetimes (τrad) are calculated. The up-conversion emission spectra of Er3+ exhibit four peaks centered at 538 nm, 554 nm, 653 nm and 822 nm assigned to 2H11/2 → 4I15/2, 4S3/2 → 4I15/2,4F9/2 → 4I15/2 and 4I9/2 → 4I15/2 transitions respectively in all samples. The maximum enhancement is evidenced at 1.5 mol% of Er2O3 by a factor of 3.11, 1.88 and 2.80 times for 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4I9/2 → 4I15/2 transitions respectively. A schematic energy level diagram is proposed. The effective band width at half maximum (FWHM) (Δλeff), stimulated emission cross-section (δPE) and the product of δPE×FWHM for 4S3/2 transitions of the glasses have also been studied and reported.