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This study looked at the thermal conductivity of translucent (Y1−xGdx)2O3 (where 0 ≤ x ≤ 1) solid solution ceramics in the temperature range from 50 K to 300 K. The samples were obtained by hot pressing from high-purity nanopowders at 1600 °C, no sintering additives were used. Compositions with cubic syngony (x ≤ 0.7) and a monoclinic one (x ≥ 0.9) were investigated. Furthermore, a dense sample of cubic Gd2O3 with a LiF sintering additive was obtained and its thermal conductivity was determined (k = 11.7 W/(m K) at 300 K). It was shown that in the range of solid solution ceramic compositions 0.2 ≤ x ≤ 0.7, the thermal conductivity was practically unchanged and close to the value k ≈ 5 W/(m K) at 300 K.

A transparent sesquioxide ceramic (Er0.07La0.10Y0.83)2O3 was fabricated by vacuum sintering at 1780 °C for 3 h with lanthana acting as a sintering additive. It was of single-phase nature (sp. gr. Ia 3 ˉ ) with a close-packed microstructure (average grain size: 17 μm, pore content: 5 ppmv) and high transparency of 80% at 1.1 μm. The La3+ ions induced additional inhomogeneous broadening in the absorption and emission spectra of Er3+ ions. For the 4I11/2→4I13/2 transition, the stimulated-emission cross-section σ SE was 1.06 × 10−20 cm2 at 2719 nm and the luminescence lifetimes of the 4I11/2/4I13/2 states amounted to 2.73/5.91 ms, respectively. A (Er0.07La0.10Y0.83)2O3 ceramic laser generated 300 mW at 2840 nm with a slope efficiency of 27.7% and a laser threshold of only 17 mW.

Broadband emission properties of Tm3+-doped parent and binary / ternary solid-solution sesquioxide laser ceramics of the system Y2O3-Lu2O3-Sc2O3 were studied with a goal of developing materials capable of generating ultrashort pulses at ~2 μm.

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