Structural and 1.8 μm luminescence of Ba(PO3)2 fluorophosphate glass

Abstract

Tm³⁺-doped fluorophosphate glasses with different Ba(PO₃)₂ concentrations were fabricated using traditional melt-quenching method. Their structure, optical properties, and thermal were subsequently analyzed using Raman, FTIR, NMR spectroscopy, absorption spectroscopy, fluorescence spectroscopy, and differential scanning calorimetry. Judd-Ofelt parameters were used to analysis of the local environment changes concentration of rare-earth ions. As Ba(PO₃)₂ increases, the P₂(O, F)₇ group transforms into PO₂⁻, resulting in an increasing Q² groups and decreasing Q⁰ and Q¹groups. At the same time, the percentage content of F–Al bonds decreased, whereas the F–P/F–Ba bonds content increased. DSC shows a ΔT range of 128–155 °C. The fluorescence spectrum shows an increasing and then decreasing trend, reaching a maximum at FP30. FP30 glass exhibits good thermal stability (144 °C), a broad and flat gain coefficient, a long fluorescence lifetime (6.82 ms) and large emission cross section (4.69 × 10⁻²¹ cm²), is a promising candidate for 1.8 μm laser and fiber-optic amplifiers.