3D printing of Nd: YAG transparent composite ceramics

The application of 3D printed transparent composite ceramics with designable gain profile in solid-state lasers has garnered increasing interest. Problems including the poor performance of slurries, defects generated in the green bodies during printing and the uncontrolled densification process between ceramics with different components have deteriorated the optical quality of transparent composite ceramics prepared by direct ink writing (DIW), leading to the limitations on the realization of high-power laser outputs. To solve this problem, a systematic investigation of Nd: YAG transparent composite ceramics was conducted throughout the fabrication process, including DIW with the capability of dual-material switching, vacuum sintering and hot isostatic pressing (HIP). First, the ceramic slurries with good printability and high solids loading were formulated by adjusting the dispersant and thickener contents. The sintering behaviors of undoped YAG and Nd: YAG ceramics were investigated to enhance the optical quality of transparent composite ceramics. The Nd ions diffusion distances of the interface between undoped YAG and Nd: YAG regions in the vertical and horizontal composite ceramics were tested and calculated to be 50.1 μm and 43.5 μm, respectively. Finally, the laser measurement of the YAG/0.3 at. % Nd: YAG/YAG transparent composite ceramic with the dimension of 3×3×4 mm3 indicated that the maximum output power of 2.15 W with the slope efficiency of 40.2% was achieved at the absorbed pump power of 5.70 W.