Optical absorption and emission properties of Pr and Er in lithium cesium mixed alkali borate glasses

This article presents the optical absorption and emission properties of Pr³⁺ and Er³⁺ in mixed alkali borate glasses of the type 68B₂O₃·xLi₂O·(32-x)Cs₂O (where x=8, 12, 16, 20 and 24). The variation of Judd-Ofelt intensity parameters (Ω_λ), the peak wavelength of the hypersensitive transitions, radiative transition probabilities (A_rad) and peak emission cross-sections (σ_p) with x in the glass matrix have been discussed in detail. The changes in position of hypersensitive transition and intensity parameters with x are correlated to the structural changes in the host matrix. The estimated radiative lifetimes (τ_R) of certain excited states of both Pr³⁺ and Er³⁺ in lithium cesium mixed alkali borate glasses are reported. Branching ratios (β) and integrated absorption cross-sections (Σ) for certain important transitions are presented. Peak stimulated emission cross-sections (σ_p) are calculated for the observed emission peaks of Pr³⁺ and Er³⁺ ions in this glass matrix.