Influence of modifier oxides on structural, thermal and optical properties of Er~(3+) doped lithium fluoroborate glass

摘要

Erbium doped lithium fluoroborate glass systems with chemical compositions Li2B4O7-BaF2-NaF-MO (where M=Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaFr-NaF-CdO-PbO containing 0.5 mol% of Er~(3+) have been prepared and investigated. The structural, thermal and optical properties of the glasses were investigated by FTIR, DSC, absorption and NIR luminescence spectra. The influence of single and double modifier oxides on the structural, thermal and optical properties of the glasses was analyzed. Judd-Ofelt (J-O) intensity parameters (Ω_λ where λ=2,4 and 6) were calculated and from these certain radiative properties are estimated. From the absorption cross-sections (σ_a), emission cross-sections (σ_e) are obtained using the McCumber theory for the transition, ~4I_(13/2)→~4I_(15/2) of Er~(3+). These values are compared with emission cross-sections (σ_p) obtained from J-O theory. It is noted that the product of the emission cross-sections and FWHM of lithium fluoroborate glasses are higher than that of phosphate and tellurite glass matrices. The gain coefficient G(A) of the present borate glass systems are also reported.