Owing to their rich color, excellent mechanical properties, and favorable biocompatibility, colored zirconia ceramics have been widely used in intelligent terminals, dental restoration, colored decorations, and other potential fields. This paper starts with the challenges faced by colored zirconia ceramics, followed by a summary of the application market of colored zirconia ceramics. Herein, we review various types of colorants and their mechanism of color development, summarize coloring methods, and analyze their advantages and disadvantages. Finally, the research progress on zirconia ceramics with red, blue, black, and other common colors is summarized, and future development directions are proposed in this review.

Fluoride laser ceramics, employed as amplification medium in solid-state lasers, have attracted considerable attention due to their excellent optical properties combined with other material parameters important for these applications, making them a largely versatile material. In this review, the fabrication and properties of fluoride laser ceramics, including CaF₂, SrF₂ and BaF₂ ceramics, are comprehensively investigated. As the state-of-art analysis shows, while some ceramic materials of this type have shown promising properties suitable for practical applications, most still require further research in the field of basic research as well. Specifically, this article reviews the state of research, identifies issues and prevailing challenges, and outlines development trends for fluoride ceramics for solid-state laser applications. The information gathered here is an important compendium of knowledge both for researchers seeking to work in this field of science, as well as a source of the latest information for experienced professionals who are already continuing pre-implementation work in this area.

Terbium aluminum garnet (Tb₃Al₅O₁₂; TAG) ceramics are among the most promising magneto–optical materials owing to their outstanding comprehensive performance. Many works have focused on improving the optical quality of TAG ceramics. A key point for improving optical quality is ensuring the accuracy of the stoichiometric ratio and avoiding secondary phases. In this work, 0, 2, 4, or 6 wt% Sc₂O₃ was added to the TAG ceramics to increase the solid solubility. The effects of Sc substitution on the crystal structure, sintering process, microstructure, optical transmittance, and magneto–optical properties of (Tb_1−xSc_x)₃(Al_1−ySc_y)₂Al₃O₁₂ (TSAG) ceramics are studied in detail. 4 wt% Sc₂O₃:TAG ceramics with an in-line transmittance of 82.2% at 1064 nm and 81.2% at 633 nm were successfully fabricated, and the Verdet constant was 164.4 rad·T⁻¹·m⁻¹ at 633 nm. Anti-site defects (ADs) and Sc replacement in TAG are further studied via first-principles calculations to determine the working mechanism of Sc. Both the experimental and calculation results show that the introduction of Sc can effectively increase the solid solubility of TAG ceramics, suppress secondary phases, and hence improve the optical transmittance.

Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam, so they are important elements in laser systems. As magneto-optical materials are the most important component in Faraday isolators, the studies on magneto-optical materials have attracted much attention these years. Tb₃Al₅O₁₂ (TAG) ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance. However, the optical quality of TAG ceramics needs further optimization to meet the application requirements. In this work, high optical quality (Tb_1−xY_x)₃Al₅O₁₂ (x = 0, 0.05, 0.1, 0.2, and 0.3) magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing (HIP) post-treatment. All the ceramics obtained showed a single garnet phase for different values of x in the range studied. The addition of Y₂O₃ was found to suppress the secondary phase and improve optical quality significantly. The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9% at 1064 nm and 82.2% at 633 nm, respectively. The Verdet constants of (Tb_1−xY_x)₃Al₅O₁₂ ceramics with x = 0, 0.05, 0.1, 0.2, and 0.3 were −188.1, −175.4, −168.5, −143.0, and −119.9 rad/(T·m), respectively. The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K) at 25 ℃, and when 20% Y was substituted in place of Tb, the thermal conductivity decreased by only 9.4%.

(Gd,Y,Ce)₃(Y_xGa_1−x)₂GaAl₂O₁₂ (GYGAG:Ce) scintillation ceramics with different Y excess, where x = 0.005−0.08, were fabricated by the solid-state reaction method. The effects of stoichiometry on the phase composition, optical quality, and microstructure of GYGAG:Ce ceramics were analyzed. GYGAG:Ce ceramics have a pure garnet phase and obtain good in-line transmittance when x < 0.04, while more Y excess leads to the creation of the secondary phase. The change of x value influences the sintering behavior of the GYGAG:Ce ceramics: The excess of Y works as the self-sintering aid and significantly reduces the sintering temperature of ceramics. When x = 0.01–0.04, the X-ray excited luminescence (XEL) spectra and light yields of GYGAG:Ce ceramics are similar. The fast scintillation decay time and afterglow intensity of GYGAG:Ce ceramics show a slight decrease with increasing x value. Finally, additional 50–500 ppm MgO and 100–500 ppm CaO were introduced to the GYGAG:Ce ceramic with x = 0.04, and both were found to significantly increase the fast scintillation component and reduce the afterglow intensity by two orders of magnitude to 0.01% after X-ray cut-off.

Ultrafine-grained Al₂O₃–rare earth:yttrium aluminium garnet (Al₂O₃–RE:YAG) (RE = Ce; Ce+Gd) composite ceramics were obtained for the first time by reactive spark plasma sintering (SPS) using commercially available initial oxide powders. The effect of key sintering parameters (temperature, dwell time, and external pressure (P_load)) on densification peculiarities, structural-phase states, and luminescent properties of composites was studied comprehensively. Differences in phase formation and densification between Ce-doped and Ce,Gd-codoped systems were shown. Parameters of reactive SPS, at which there is partial melting with the formation of near-eutectic zones of the Al₂O₃–YAG system/coexistence of several variations of the YAG-type phase, were established. Pure corundum–garnet biphasic ceramics with an optimal balance between microstructural and luminescence performance were synthesized at 1425 ℃/30 min/30–60 MPa. The external quantum efficiency (EQE) of the phosphor converters reached 80.7% and 72% with close lifetime of ~63.8 ns, similar to those of commercial Ce:YAG materials, which is promising for further applications in the field of high-power white light-emitting diodes (WLEDs) and laser diodes (LDs).

As a promising magneto-optical (MO) material applied in Faraday isolators, magneto-optical ceramics possess excellent comprehensive properties and have attracted much attention these years. Herein, we review the fabrication and properties of magneto-optical ceramics including garnet, sesquioxide, and A₂B₂O₇ ceramics. Some of the ceramics have been proved to possess applicable performance, while further studies are still needed for most of the magneto-optical ceramics. Aiming at the application for isolators, the research status, existing problems, and development trends of magneto-optical ceramics are shown and discussed in this review.

The major advantage of laser lighting over white light-emitting-diode is the possibility to achieve ultra-high luminance. However, phosphors usually suffer laser-induced luminescence saturation, which limits the peak luminance of laser lighting devices. The aim of the present study is to develop LuAG:Ce/Al₂O₃ composite ceramics (LACCs) with a high saturation threshold for high-luminance laser lighting. Owning to the rigid crystal structure, proper synthetic process, and optimized thermal design, the LACCs possess small thermal quenching (16% loss in luminescence at 225 ℃), high quantum yield (> 95%), and excellent luminescence properties. When the LACCs are irradiated by blue laser diodes in a reflection mode, a high luminous flux of 4634 lm and luminous efficacy of 283 lm·W⁻¹ are realized. Furthermore, they show no sign of luminescence saturation even when the power density reaches 20.5 W·mm⁻². With these favorable properties, the designed LACCs show great potential in high-luminance laser lighting.

Garnet ceramic scintillators are a class of inorganic scintillation materials with excellent overall performance. The flexibility of cation substitution in different lattice positions leads to tunable and versatile properties and a wide range of applications. This paper starts with an overview of the development history of the inorganic scintillation materials, followed by a description of major preparation methods and characterization of garnet scintillation ceramics. Great progress obtained in recent years consisting in applying the band-gap and defect engineering strategies to the garnet scintillation ceramics is reviewed. Finally, the respective problems in the preparation and performance of multicomponent garnet single crystals and ceramics and the effective solutions are discussed. The garnet scintillation ceramics with the highest application potential are summarized, and the future development directions are proposed.

Fine grained 8 mol% yttria-stabilized zirconia (8YSZ) transparent ceramics with high optical and mechanical properties were fabricated by air pre-sintering and hot isostatic pressing (HIP) using commercial 8YSZ powders as the raw material. The pre-sintered ceramics with fine grains and appropriate relative density play a key role to achieve high transparency and suppressed grain size after HIP post-treatment at relatively low temperatures. With the increase of HIP temperature from 1350 to 1550 ℃, the in-line transmittance of 8YSZ ceramics at 600 nm increases from 56.9% to 71.5% (2.5 mm in thickness), and the average grain size increases from 2.4 to 16.3 μm. The corresponding bending strength of 8YSZ transparent ceramics decreases from 328±20 to 289±19 MPa, the hardness (H) decreases from 12.9±0.1 to 12.5±0.2 GPa, and the fracture toughness (K_IC) decreases from 1.30±0.02 to 1.26±0.03 MPa·m^1/2. Systematical investigations were carried out to study the combination of high optical transparency and excellent mechanical properties in 8YSZ ceramics.