Fabrication and laser operation of Yb:Lu 2 O 3 transparent ceramics from co‐precipitated nano‐powders

In this article, 5 at.% Yb:Lu 2 O 3 transparent ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) posttreatment using co‐precipitated nano‐powders. The influence of precipitant molar ratio, ammonium hydrogen carbonate, to metal ions (AHC/M 3+ , R value) on the properties of Yb:Lu 2 O 3 precursors and calcined powders was investigated systematically. It was found that the powders with different R value calcined at 1100°C for 4 hours were pure cubic Lu 2 O 3 but the morphologies of precursors and powders behaved differently. The opaque samples pre‐sintered at 1500°C for 2 hours grew into transparent ceramics after HIP posttreatment at 1750°C for 1 hour. The final ceramic with R  = 4.8 showed the best optical quality with the in‐line transmittance of 79.7% at 1100 nm. The quasi‐CW laser operation was performed at 1034 nm and 1080 nm with a maximum output power up to 8.15 W as well as a corresponding slope efficiency of 58.4%.