Er3+-doped strontium lithium bismuth borate glasses for broadband 1.5 μm emission – Structural and optical properties

Strontium lithium bismuth borate glasses (SLBiB) doped with various concentrations of Er3+ were prepared using conventional melt quenching technique and investigated their structural and optical properties. The structural properties were investigated using XRD and FTIR spectra. XRD analysis confirmed amorphous nature of glass samples. FTIR spectra were used to find the functional groups in the glass matrices. Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra. Judd–Ofelt (J–O) theory has been applied to evaluate J–O intensity parameters, Ωλ (λ = 2, 4 and 6) and are used to estimate radiative properties like transition probabilities (A), branching ratios (β) and radiative lifetimes (τR) for certain transitions. Among all transitions, 4I13/2 → 4I15/2 transition shows higher branching ratio as well as higher radiative lifetime values. Peak emission-cross sections (σe), full-width at half maximum (FWHM) and products of stimulated emission cross-section and full-width at half maximum (σe × FWHM) were calculated for the observed emission transition, 4I13/2 → 4I15/2. These values are higher for 1.0 mol% of Er3+ glass matrix among all glass matrices. Using the Mc-Cumber theory, stimulated emission cross-sections (σe) were obtained from absorption cross-section (σa).