Preliminary results on Sm3+:YSAG transparent ceramic

Cubic Y3ScxAl3-xO12 (YSAG) crystals are attractive laser-host materials due to their high thermal conductivity, broad spectral region, chemical stability, strong Stark splitting and relatively low phonon energies. However, it is very difficult to grow large-size single crystals with high quality because of the high melting point (~19500C). On the other hand, polycrystalline ceramics have lower sintering temperature, about 1750oC. Moreover, because of the absence of segregation coefficient, ceramics can be doped with a higher fraction of active ions and can be fabricated in larger sizes compared to single crystals. In this work we present the results of our research on the production of samarium doped YSAG (Sm3+:YSAG) transparent polycrystalline ceramics for visible laser emission [1, 2]. High purity ?-Al2O3 (99.99+% purity, ~100-nm diameter), Y2O3 (99.99% purity, 20 to 40 nm diameter), Sc2O3 and Sm2O3 (99.99% purity) powders were used as starting materials. The selected composition is Sm0.03Y2.97Sc2Al3O12. The powders were magnetically mixed in stoichiometric ratio in anhydrous ethylic alcohol for 24 h. As sintering additive, 0.5 wt.% of tetraethyl orthosilicate (TEOS) was used. The alcohol solvent was removed by drying the slurry at 800C. The dried powder was milled and pressed at low pressure (10 MPa) into pellet with half of inch diameter in a metal mold and then cold isostatically pressed at 240 MPa. Before sintering, the sample was heated at 8000C for removing organic substances used in preparation.