# Gadolinium gallium garnet, Gd3Ga5O12 (GGG)

Gadolinium gallium garnet (Gd3Ga5O12, or GGG) is a synthetic crystalline material belonging to the garnet group. It is well-known for its use as a substrate for magneto-optical films and for the epitaxial growth of other garnet materials like yttrium iron garnet (YIG). GGG's thermal and mechanical stability make it suitable for high-temperature applications. Its optical properties are also noteworthy; the material is transparent over a broad range of wavelengths from the ultraviolet to the near-infrared, with a refractive index of approximately 1.97 at 632.8 nm. GGG is often employed in optical isolators, circulators, and other magneto-optic devices, as well as in certain laser applications where a high-quality substrate material is required.

## External links

- Gadolinium gallium garnet - Wikipedia