Transparent Yb:YAG ceramics, layered in situ composites

This work reports on the fabrication of transparent YAG ceramic architectures with controlled Yb content via spray drying, subsequent uniaxial pressing followed by cold isostatic pressing, and solid state reaction sintering in high vacuum with TEOS as sintering additive. Samples of undoped YAG and 5 and 10 at.% Yb:YAG were prepared this way, and their microstructure and optical transmittance were characterized. Further, the fabrication of a transparent ceramic sample with layers of undoped and 10 at.% Yb-doped YAG is shown. All the samples were sintered to full density and transparent quality. The prepared ceramics had homogeneous microstructure with grain size about 30-50 ?m and transmittance values 79-81%. In the case of layered sample, a zone with Yb concentration gradient of a thickness of less than 300 ?m was observed between the doped and undoped part. This shows good control of the dopant distribution, and the presented method allows the production of thin disk laser architectures.