Preparation of transparent erbium-ytterbium co-doped yttrium aluminum garnet Er,Yb:YAG ceramics with the aid of freeze granulation
SZYSIAK A. 1, PODNIESI?SKI D. 1, W?GLARZ H. 1, CHAIKA M. 2
1 ?ukasiewicz Research Network - Institute of Microelectronics and Photonics, Warsaw, Poland; 2 Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroc?aw, Poland
The good spectroscopic parameters of Er,Yb:YAG single crystals and the high temperature and mechanical resistance characteristic for yttrium aluminium garnets cause that this material can be widely used in laser technology as a material which generate in "eye-safe" region.
In this presentation, we report, the preparation of transparent Er,Yb:YAG ceramics by using freeze granulation process and solid state synthesis. Firstly aqueous slurries of pure oxides were prepared through mixing the powders in a planetary mill in water with Duramax B-1000 as a binder, Dolapix CE64 as a dispersing agent and laboratory-prepared octaanion as a source of Si4+ ions. Slurries were sprayed into the liquid nitrogen in order to form granules which were immediately afterwards freeze dried. The granulates were pressed (under both uniaxial and isostatic pressure) into 20 mm pellets.
The samples were fired up in order to remove organic additives and afterwards sintered under vacuum. The samples were annealed again in the air. Received ceramics were abraded and polished up bilaterally to mirror-like paralel surfaces with 1 or 2 mm thickness.
The influence of sintering temperature and time as well as temperature and annealing time on the optical properties of ceramics was investigated. The optical transmission of Er,Yb:YAG ceramics was measured in the range 200÷3000 nm. The samples were subjected to phase analysis by XRD diffraction, surface microstructure analysis by SEM scanning electron microscopy, analysis of the chemical composition of the sample by EDS spectroscopy, and then the photoconversion and absorption properties were examined.