Thermal Stability, Mechanical and Optical Properties of Er/Yb Co-Doped La₂O₃–Al₂O₃–ZrO₂–TiO₂ Glasses Prepared by Containerless Aerodynamic Levitation Technique

A series of La₂O₃–Al₂O₃–ZrO₂–TiO₂ glasses co-doped with Er³⁺ and Yb³⁺ ions ([30 – (30/88)(x + y)] La₂O₃–[58 – (58/88)(x + y)]Al₂O₃–4ZrO₂–8TiO₂, x = 2 mol %, and y = 4, 8, 12, 16, 20 mol %, abbreviated as LAZT: xEr³⁺/yYb³⁺) were synthesized using a containerless aerodynamic levitation technique. The amorphous nature, thermal stability, mechanical properties, elemental distribution uniformity, optical transmittance, and refractive index dispersion were characterized. The prepared LAZT: xEr³⁺/yYb³⁺ glasses exhibit homogeneous distribution of all elements, exceptional thermal stability (glass transition temperature T_g > 850°C), superior mechanical properties, high refractive index (~1.9) and Abbe number (>40). The glass-forming ability of the system, initially increasing and then decreasing with increasing the Yb³⁺ concentration, is overall below 100°C, which is relatively poor, and highlights the advantage of containerless technique in preparing the LAZT-based glasses. The above results show that the LAZT: xEr³⁺/yYb³⁺ glasses prepared by the containerless technique are suitable for optical research, practical industrial and up-conversion luminescence applications.