Yttrium Aluminium Granat (YAG)

Material
YAG
 
Yttrium Aluminium Garnet (Y3Al5O12) is a new substrate and optical material that can be used for UV and IR optics. It is useful for optical components in wide spectrum band from 250 – 5000 nm. The mechanical and chemical stability of YAG is similar to that of Sapphire, but YAG is not birefringent and can be polished to surface quality Scratch/Dig – 10/5. YAG shows no trace absorption in the 2 – 3 µm region where Glasses tend to be highly absorbent because of the strong H2O band. YAG is commonly used for high-temperature and high-energy applications, in industrial, medical and scientific fields due to high strength and another advantages, like physically hardness, high bulk damage threshold, high index of refraction, excellent thermal conductivity and no absorption in the 2 – 3 µm range.

We use for our optics high quality crystals growth on the Czochralsky technique. The undoped YAG single crystals can be polished to a high quality laser finish, thus making an ideal substrate for robust dielectric optical components, lens ducts, prisms and mirrors.
Properties
Optical Properties
Transmission range in µm @10% min. 0.18 - 6.4
Transmission range in µm @50% min. 0.2 - 6.2
Refractive index @633nm 1.829
Reflection losses in % at 1 surface 7.9 @3µm
Reflection losses in % at 2 surfaces
dn/dT in 1/K 9.1· 10-6 @1064nm
Physical Properties
Density in g/cm³ 4.56
Melting point in °C 1950
Specific heat capacity in J/(kg · K) 628
Thermal Conductivity in W/(m · K) 13.1
Thermal Expansion in 1/K 7.8 · 10-6 (111)
7.7 · 10-6 (110)
8.2 · 10-6 (100)
Dielectric constant 7.75
Solubility in water in g/100g unsoluable
Mohs hardness 8 - 8.5
Knoop hardness in kg/mm² 1350<100>
Material type Single crystal, synthetic
Crystal type cubic
Crystal structure m3m
Lattice constant in Å a = 10
Elastic coeficients in GPa C11 = 333
C12 = 111
C44 = 114
Young's Modulus (E) in GPa 280
Shear Modulus (G) in GPa 113
Bulk Modulus (K) in GPa 180
Rupture Modulus in MPa 150
Apparent elastic limit in MPa 280
Poisson ratio 0.24
Spectral Properties