La2O3, Y2O3, ZrO2, and MgO+TEOS were added as the sintering aid to prepare Yb3+:Y3Al5O12 transparent ceramics. Pre-calcination was adopted to improve the crystalline quality and morphology of the commercially available Y2O3 raw powders. The non-stoichiometricaly doped La2O3, Y2O3, and ZrO2 enhanced the grain boundary mobility so fast that
abnormal grain growth occurred and pores tended to be enclosed in these grains. It was found that MgO+TEOS had a
positive effect on full densification of the Yb:YAG ceramics. The grain boundaries moved moderately so that pores could
be eliminated well and meanwhile the grains would not get too large.
Laser output experiment was also carried out for the Yb:YAG transparent ceramics.