Enhancing the structure and properties of fluoro-sulfo-phosphate laser glass via Zn(PO3)2 incorporation

Multi-anion fluoro-sulfo-phosphate (FSP) glass with the compositions of KPO3–Zn(PO3)2–AlF3–Na2SO4 (labeled as KZFSP) was designed. Effects of Zn(PO3)2 incorporation on glass structure and properties were investigated through Raman and Fourier transform infrared (FTIR) spectrometers, solid-state nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) measurements, etc. Structure analyses reveal that adding Zn(PO3)2 raises the polymerization degree of skeleton structure and enhances the bonding strength between cations and anions, which improves the physicochemical properties. Optimized KZFSP glass shows excellent anti-crystallization ability (ΔT >224 °C), mechanical properties and chemical durability compared with KPO3-based FSP glass. Nd3+-doped KZFSP glass exhibits a relatively large figure of merit (~1.02 × 10–23 cm2•s) and low saturation intensity (~1.84 × 108 W•m–2), which is a promising material for high-performance single-frequency or high-repetition-frequency lasers.