Gadolinium Gallium Garnet (GGG)
Gadolinium Gallium Garnet (GGG) is a synthetic single crystal, with a high mechanical and chemical resistance, high thermal conductivity as well as large heat capacity. GGG crystals are grown by the Czochralski method. They are considered promising for the fabrication of optical components and substrates for magneto-optical films. Furthermore, it can be used as an optical insulator formed from a YIG or BIG film on the GGG substrate.
The GGG single crystal is an important substrate for microwave insulators and, thanks to special thermomagnetic properties, it is used in cryogenics for cooling objects at temperatures close to absolute zero.
Due to its high refractive index, a lens made of gadolinium gallium garnet can replace an entire lens system, which is especially important in compact devices. Optics made of GGG are used in lasers, telecommunications and electronics.
Optical and spectral properties
Transmission range in µm
Refractive index @480 nm
Refractive index @633 nm
Refractive index @1064 nm
Density in g/cm3
Melting point in °C
Thermal conductivity in W/(cm · K)
Thermal expansion in 1/°C
8,2 · 10-6
single crystalline, synthetic
Lattice constant in Å
sample thickness: 0,52 mm