Nd:LuAG transparent ceramics fabricated from nano-powders synthesized by the co-precipitation method

Nd∶LuAG transparent ceramics, due to their excellent optical, mechanical, and thermodynamic properties, as well as their moderate saturation fluence, demonstrate greater development potential as a gain medium in high repetition rate high-energy solid-state lasers. The co-precipitation method for synthesizing nano-powders offers advantages such as high chemical homogeneity and low synthesis temperature. Nano-powders with high sintering activity can significantly reduce the densification temperature and time, as well as greatly decrease the grain size of ceramics. It is a commonly used and effective method for preparing garnet-based transparent ceramic powders. Using nitrate as raw material and ammonium bicarbonate as precipitant, 1at.% Nd:LuAG nano-powders were prepared via the co-precipitation method. The nano-powders exhibit a single LuAG phase with an average primary particle size of approximately 97nm. The 1at.% Nd:LuAG transparent ceramics were prepared by vacuum pre-sintering at 1450~1650℃ for 3h and HIP post-treated at 1500℃ for 3h under 200MPa. The effect of the vacuum pre-sintering temperature on the microstructure and optical transmittance was investigated. The experimental results indicate that when the vacuum pre-sintering temperature is 1550℃, the in-line transmittance of the 1.5mm thickness 1at.% Nd:LuAG transparent ceramics with an average grain size of 927nm is 83.6% at 1064nm. The successful preparation of fine-grained, high-optical-quality Nd:LuAG transparent ceramics is of great significance for enhancing the performance of high repetition rate nanosecond high-energy solid-state lasers.