Laser oscillation and luminescence of Nd³⁺- and Eu³⁺-doped Lu₂O₃ transparent ceramics fabricated by spark plasma sintering

Highly transparent Lu₂O₃ ceramics with and without Nd³⁺ and Eu³⁺ dopants were fabricated by spark plasma sintering using a two-step pressure profile. A transmittance at 1080nm for the Lu₂O₃ ceramics sintered by as-received powders at a pressure of 100MPa was 57%. By sintering ball-milled Lu₂O₃ powders with 0.2 mass% LiF at a preloading pressure of 10 MPa, final pressure of 100 MPa, heating rate of 0.17Ks^-1, and sintering temperature of 1723 K, the transmittance at 1080nm of the Lu₂O₃ ceramics reached 8082% after annealing in air, i.e., nearly 100% of the theoretical value for no scattering. Finally, laser oscillation was demonstrated using 1 at.% Nd³⁺:Lu₂O₃ transparent ceramics at 1076 and 1080nm wavelengths, e.g., laser output of 0.2W and slope efficiency of 14% for straight-cavity configuration.