Fabrication, microstructure and optical properties of large-sized Nd:YAG and composite Yb:YAG transparent ceramic slabs

Large-sized Nd:YAG and composite Yb:YAG transparent ceramic slabs of high quality were fabricated by the conventional solid-state reaction sintering technique. The Yb:YAG transparent ceramic slabs were surrounded by undoped YAG transparent ceramics and this composite structure was built in the process of ceramic shaping. The difference in microstructure between Yb:YAG and YAG transparent ceramics was not observed and the composite Yb:YAG slabs showed fully dense and pore-free microstructure. The in-line transmittances at 400 nm reached 81.7% and 79.7 % for YAG and Yb:YAG transparent ceramics, respectively, indicating good optical quality of the composite ceramic slab. And the optical transmission micrograph was very homogeneous with only a few isolated scattering centers. These results suggested that building composite structure in the process of ceramic shaping was a simple and reliable technical scheme. Moreover, the large-sized Nd:YAG transparent ceramic slab with size of 150.0 mm x 50.0 mm x 4.0 mm was also prepared. The calculated absorption coefficient was about 0.002 cm(-1) @1064 nm, which suggested that the optical quality of this Nd:YAG transparent ceramic slab had reached the level of Nd:YAG crystals.