Up-conversion and near-infrared luminescence in Er3+ -doped La2O3-PbO-B2O3-TeO2 glasses for the generation of fibre amplifiers and green LED applications

In this work, we demonstrate the influence of Er3+ ions on the spectroscopic properties of 5La2O3-15PbO-(50-x)B2O3-xEr2O3-30TeO2 glasses doped with x = 0.1, 0.5, 1.0, 2.0 & 3.0 mol% of Er3+ were prepared with the melt-quenching method. The structural, fluorescence and decay time properties were examined, and the theoretical model, JO, Mc, and FL theory, was utilised to confirm the experimental findings. It is evident from XRD results that the glasses do not possess a well-defined crystalline structure. Instead, they exhibit a random arrangement of atoms and molecules, indicating an amorphous characteristic. JO analysis yields the stimulated-emission cross-section (2.12 ×10−20 for LPBTE1 glass, which is highest among other prepared glasses) & intensity parameters (Ω2,4,6) show Ω2 > Ω6 > Ω4 trend indicating the covalency nature. Predominant luminescence in the NIR region, emission peaked at 1537 nm was observed, which was ascribed to the 4I13/2 ⟶ 4I15/2 transition. The temporal decay rate decreased from 0.83 ms to 0.27 ms with an increase in the concentration of Er3+ from 0.1 to 3 mol%, which is due to the self-quenching action of the cross-relaxation channels. Furthermore, using Mc-Cumber's theory the peak values for the emission and absorption cross-sections are evaluated and found in good agreement with each other. The gain profile demonstrates more than 40% population inversion between 1530 and 1610 nm in the C +L band. In addition, the up-conversion of 4S3/2 ⟶ 4I15/2 transitions at 544 nm exhibits green emission shows two-photon absorptions. Overall, the investigated results demonstrate that the prepared Er3+ -doped La2O3-PbO-B2O3-TeO2 glasses are the best choice for optical fibre applications.