Er³⁺-doped transparent glass ceramics containing micron-sized SrF₂ crystals were obtained by direct liquid-phase sintering of a mixture of SrF₂ powders and precursor glass powders at 820 °C for 15 min. The appearance and microstructural evolution of the SrF₂ crystals in the resulting glass ceramics were investigated using X-ray diffraction, field-emission scanning electron microscopy and transmission microscopy. The SrF₂ crystals are ~15 μm in size and are uniformly distributed throughout the fluorophosphate glass matrix. The glass ceramics achieve an average transmittance of 75% in the visible region and more than 85% in the near-IR region. The high transmittance of the glass ceramics results from matching the refractive index of the SrF₂ with that of the precursor glass. Energy dispersive spectroscopy, photoluminescence spectra and photoluminescence lifetimes verified the incorporation of Er³⁺ into the micron-sized SrF₂ crystals. Intense 2.7 μm emissions due to the ⁴I_11/2 → ⁴I_13/2 transition were observed upon excitation at 980 nm using a laser diode. The maximum value of the emission cross section of Er³⁺ around 2.7 μm is more than 1.2 × 10⁻²⁰ cm², which indicates the potential of using transparent glass ceramics containing micron-sized SrF₂ crystals for efficient 2.7 μm lasers and amplifiers.

Transparent glass ceramics containing CaF₂ micron-sized crystals were prepared using a modified liquid-phase sintering route.

The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG) powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC) was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (>15 h) with high terminal pH value (>7.80) resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission >75% at 1064 nm were fabricated using these well dispersed nano LuAG powders.

In the present study, a tough tetragonal zirconia polycrystalline (Y-TZP) material was developed for use in high-speed infrared windows and domes. The influence of the preparation procedure and the microstructure on the material’s optical properties was evaluated by SEM and FT-IR spectroscopy. It was revealed that a high transmittance up to 77% in the three- to five-micrometer IR region could be obtained when the sample was pre-sintered at 1225 °C and subjected to hot isostatic pressing (HIP) at 1275 °C for two hours. The infrared transmittance and emittance at elevated temperature were also examined. The in-line transmittance remained stable as the temperature increased to 427 °C, with degradation being observed only near the infrared cutoff edge. Additionally, the emittance property of 3Y-TZP ceramic at high temperature was found to be superior to those of sapphire and spinel. Overall, the results indicate that Y-TZP ceramic is a potential candidate for high-speed infrared windows and domes.