Highly transparent Nd³⁺: Lu₂O₃ produced by spark plasma sintering and its laser oscillation

Laser oscillation was demonstrated using a 1 at.% Nd³⁺-doped Lu₂O₃ (Nd³⁺:Lu₂O₃) transparent ceramic produced by spark plasma sintering. Nd₂O₃, Lu₂O₃, and LiF commercial powders were mixed by ball milling and were sintered at 1723 K using a two-step sintering profile. After the transparent Nd³⁺:Lu₂O₃ ceramic was annealed in air, its transmittance at 1076 nm reached 81.8%, which was close to the theoretical value for Lu₂O₃ (82.2%). The absorption cross-section at 806 nm was 1.29 × 10^-20 cm², and the fluorescence decay time at 1076 nm was 229 μs. The laser oscillation of Nd³⁺:Lu₂O₃ ceramic for the transition from ⁴F_3/2 to ⁴I_11/2-specifically, at 1076.7 and 1080.8 nm-was simultaneously obtained, with a laser output of 0.21 W and slope efficiency of 14%.