Yttrium aluminate garnet (YAG, Y₃Al₅O₁₂) is an important laser material with excellent chemical stability, thermal and good optical properties, and high temperature creep resistance. It has proved to be one of the most promising laser materials for many kinds of laser devices.

Cerium-activated yttrium aluminate (Y3Al5O12: Ce3+) exhibiting a garnet structure has been widely utilized in the production of light-emitting diodes (LEDs) as a yellow emitting phosphor. The commercialized yttrium aluminate garnet (YAG) phosphor is typically synthesized by a solid-state reaction, which produces irregularly shaped particles with a size of several tens of micrometers by using the top-down method.

Ceramic powder processing within the Y2O3-Al2O3 system has largely been intended for optical and structural applications. In this system, three stable yttrium aluminates exist with different polymorphs, perovskite-based orthorhombic YAlO3 (YAP), monoclinic Y4Al2O9 (YAM) and garnet Y3A15O12 (YAG). The latter is rich in Al2O3 and crystallizes with cubic symmetry. It does not exhibit any birefringence effects at the grain boundaries and hence results in high in-line transparency

Synthetic yttrium aluminate garnet Y3Al5O12 (YAG) is one of the most important materials used since the 60’s for the production of optoelectronic devices. Doped in the monocrystallization process with a number of the lanthanide-family metals it is used, among others, for the production of lasers.