Enhancing thermal shock stability of Yb3+-doped Zn(PO3)2-Ba(PO3)2-AlF3-KF fluorophosphate glass

Abstract

The 1.0 μm ultra-short pulse laser is distinguished by its high energy, short pulse width, and intense peak power density, serving various applications in materials processing and biomedicine. Yb ions play a crucial role in this wavelength range, yet achieving high doping levels in commercial Yb-doped silica fibers is challenging due to their dense network structure. Here, we present the design and fabrication of a fluorophosphate (FP) glass with high thermal shock stability (figure of merit is 0.95), achieved through thermodynamic prediction methods, ion field strength analysis, and glass structure theory. By modifying the composition of high-field-strength cations, we not only alter the fundamental properties of the glass but also enhance its thermomechanical performance. Specifically, Yb³⁺-doped Zn(PO₃)₂-Ba(PO₃)₂-AlF₃-KF FP glass (Yb₁₀-ZBAFP10) exhibits a high emission cross-section (0.74×10⁻²⁰ cm² at ∼1008 nm), a low level of minimum population inversion (β_min=0.09), and minimum pump intensity (I_min=1.75 kW/cm²). Furthermore, it demonstrates a stable fluorescence lifetime within the temperature range of 298 ∼ 473 K. These findings highlight the potential of Yb³⁺-doped FP glass for applications demanding high thermal shock stability, particularly in high repetition rate ultra-short pulse laser systems.