New double-sintering aid for fabrication of highly transparent ytterbium-doped yttria ceramics

Highly transparent ytterbium-doped yttria (Yb:Y2O3-ZM) ceramic was demonstrated with ZrO2–MgO as double-sintering aid by using a pressureless sintering method for the first time. The Yb:Y2O3-ZM ceramics wafer with 17 mm in diameter and 2.5 mm thick had an average grain size of 25 μm and a transmittance at 2000 nm of as high as 81.5%, which is near theoretical value of the material. In contrast, it was difficult to obtain transparent ytterbium-doped yttria ceramics with ZrO2 or MgO as single aid. The product of emission cross section and lifetime (στ) was 8.94 × 10−24 cm2s, which means that the Yb:Y2O3-ZM transparent ceramics would be one promising laser material.