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Gallium Arsenide (GaAs) Crystal
Gallium Arsenide, GaAs crystal has special applications in far IR optics and lens
Property of GaAs Crystal
Transmission Range : 1 to 16 µm
Refractive Index : 3.2727 @ 10.33 µm
Reflection Loss : 44% @ 10.33 µm
Absorption Coefficient : 0.01 /cm
dn/dT : 147 x 10E-6/°C @ 10 µm
dn/dµ = 0 : 6.3 µm
Density : 5.315 g/cm³
Melting Point : 1511 °C
Thermal Conductivity : 48 W /m /K @ 273K
Thermal Expansion : 5.7 x 10E-6 /°C at 300K
Hardness : Knoop 750
Specific Heat Capacity : 360 J /Kg /K
Dielectric Constant : 12.91 at low frequencies
Youngs Modulus (E) : 84.8 GPa
Bulk Modulus (K) : 75.5 GPa
Apparent Elastic Limit : 71.9 MPa
Poisson Ratio : 0.31
Solubility : Insoluble in water
Molecular Weight : 144.64
Class/Structure: Cubic ZnS, F43m, (100) cleavage
- GaAs crystal is nearly as hard, strong and dense as Germanium.
- GaAs crystal is commmonly used in applications where toughness and durability
are of great importance.
- GaAs crystal has a low absorption coefficient of 0.01 /cm from 2.5 to 12 µm
- Optical grade GaAs crystal is generally more expensive than Germanium
- GaAs is diamond turnable.
- Typical Application: Thermal imaging, CO2 laser systems, FLIR.
Specifications of GaAs product
Orientation: (100) 0° +/-0.5°, (100) 2° +/-0.5° off toward <111>,
(100) 15° +/-0.5° off toward <111>
Surface Finish: Typical 40-20, 60-40 80-50 or 120-80 scratch-dig depending
upon system performance requirements.
Surface Flatness: Ranges from 1/2 wave to 2 waves @633nm depending on
the system performance requirements.
AR Coating options: BBAR for 3 to 5µm or 8 to 12µm spectral
region. Many other specialized bands are possible within the 2 to 15µm
Standard Size: Dia.2" x 0.35mm, Dia.100 x 0.35mm, 25x25x0.35mm, 10x10x0.35mm,
Surface Roughness(Ra): <=5 Å