Structure and physical properties of Ba(PO3)2–AlF3–BaSO4 fluoro-sulfo-phosphate glasses

Alkali-earth-metaphosphate-based fluoro-sulfo-phosphate M(PO 3 ) 2 –AlF 3 –MSO 4 (MPFS, M = Ca, Sr, Ba) glasses have been developed via simultaneously incorporating fluoride and sulfate into metaphosphate glass. Their glass-forming regions were efficiently determined under the guidance of thermodynamic calculation method. The physical and structural properties of BaPFS glass were investigated in detail. Furthermore, near-infrared spectroscopic properties of Er 3+ -doped BaPFS (Er–BaPFS) glass were studied. Physical parameters, such as Abbe's number ν d (55-75) and nonlinear refractive index n 2 (1.17-1.86 × 10 −13 esu), of BaPFS glass are strongly depended on P/F/S ratio. The structure of BaPFS glass gradually depolymerizes and tends to become multianionic when Ba(PO 3 ) 2 is substituted by AlF 3 and BaSO 4 . Anion-substitution strategy effectively modulates the property and structure of glass, providing a scheme to derive glass materials. In addition, enhanced emission at ~1.5 μm has been observed from Er–BaPFS glass along with large emission cross section (5.0-5.5 × 10 −21 cm 2 ) and long lifetime (6.7-7.3 ms), resulting in large figure of merit (3.46-3.84 × 10 −23 cm 2 ·s), which is a promising candidate for solid-state laser.