Gadolinium Gallium Garnet (GGG)
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 | |
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Transmission range in µm | 0,3‐7,0
|
Refractive index @480 nm | 1,97
|
Refractive index @633 nm | 1,96 |
Refractive index @1064 nm | 1,95 |
Physical properties | |
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Density in g/cm3 | 7,08
|
Melting point in °C | 1750
|
Thermal conductivity in W/(cm · K) | 7,05
|
Thermal expansion in 1/°C | 8,2 · 10-6
|
Dielectric constant | 30
|
Mohs hardness | 7,5 |
Material type | single crystalline, synthetic
|
Crystal type | cubic |
Lattice constant in Å | 12,383 |
Spectral properties | |
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sample thickness: 0,52 mm |