# Progress in Transparent Nano-Ceramics and Their Potential Applications
Compared with common optical function transparent single crystal or glass materials, transparent nano-ceramic materials have obvious advantages in their optical function effect, mechanical and thermal properties, low cost, and large size (compared with single crystal materials). At the same time, being ceramic materials, they have high strength and hardness, high-temperature resistance, and corrosion resistance, which are better than general optical materials [11]. With the improvement of the performance of transparent nano-ceramics, therefore, their functional applications have also been further developed. Research in many fields is gradually becoming commercialized, and the market potential is larger in the future. For example, transparent nano-ceramics have been used in laser gain media, transparent armor, aerospace windows, solid-state lighting, magneto-optic material, and other fields [2; 11], as shown in Figure 2.  
In this study, published literature was selected from databases such as Web of Science, Google Scholar, CNKI, and the Engineering Index, as well as publishers' databases, such as Elsevier, IEEE Xplore, and Springer. A total of nearly 130 related documents were collected, and 100 documents are reviewed and cited in this study. This literature covers the applications of transparent nano-ceramics. Among them, Web of Science, IEEE Xplore, and other academic databases are rich in literature with a wide range of research. Figure 2: Performance requirements and applications of transparent nano-ceramics. There are also many excellent Chinese journals and dissertations in the research results included by CNKI, so we also chose a small number of classic Chinese journals. Nano powder, microstructure, and preparation methods are all the key points that need to be considered in the study of transparent nano-ceramics. Therefore, when searching literature, keywords related to transparent nano-ceramics (such as \"nano-ceramics\", \"nano powder\", \"microstructure\", and \"preparation method\") and keywords related to material properties (such as \"optical transmittance\", \"IR transmittance\", \"magneto-optical material\", and \"mechanical strength\") were used. Categories and application areas of nanomaterials (e.g., \"magneto-optical transparent nano-ceramics\", \"armor transparent nano-ceramics\", \"electro-optical transparent nano-ceramics\", and \"scintillation transparent nano-ceramics\") were also indexed. Then, this review summarizes the different applications of transparent nano-ceramics, mainly including laser transparent nano-ceramics, magneto-optical transparent nano-ceramics, transparent armor nano-ceramics, electro-optical transparent nano-ceramics, and scintillation transparent nano-ceramics. Section 2 reviews the research progress of transparent nano-ceramics in solid-state laser applications, focusing on the influence of the controllable doping of rare earth ions on their performance and the realization of large-scale fabrication technology. In Section 3, we summarize the latest research progress of magneto-optical transparent nano-ceramics, mainly including terbium gallium garnet (Tb\({}_{3}\)Ga\({}_{5}\)O\({}_{12}\), TGG) transparent nano-ceramics and terbium aluminum garnet (Tb\({}_{3}\)Al\({}_{5}\)O\({}_{12}\), TAG) transparent nano-ceramics, and we compare their properties and predict their future potential applications. Section 4 mainly reviews the research progress of transparent armor nano-ceramic materials, represented by MgAl\({}_{2}\)O\({}_{3}\) and AlON. The potential applications of transparent armor nano-ceramic are aerospace windows, missile fairings, bulletproof windows, and other fields, which require high hardness and strength, good wear resistance, and impact resistance. In Section 5, we report the progress in electro-optical transparent nano-ceramics and scintillation transparent nano-ceramics. The influence of the material-fabrication process on the electro-optic effect or luminous intensity is compared.