Optics
Germanium (Ge)
Use Germanium's unique combination of high refractive index and excellent hardness to build durable, low-power imaging and laser systems with a minimum component count.
Germanium (Ge) is ideal for applications where ruggedness and durability are important, and Ge optics can withstand optical powers in the range of 50-100 watts. Its high refractive index enables its use as a beamsplitter without additional coating.
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Germanium (Ge) Characteristics
Coherent supplies Ge substrates of up to 150 mm diameter, and carefully monitors 10.6 µm absorptivity to ensure that thermal runaway and fracture do not occur.
Ge Material Properties |
|
Physical Properties |
|
Young’s Modulus |
100 GPa (12.04 x 106 psi) |
Rupture Modulus |
93 MPa (20,000 psi) |
Knoop Hardness |
692 kkg/mm² |
Density |
5.32 g/cm³ |
Poisson’s Ratio |
0.27 |
Thermal Properties |
|
Thermal Conductivity @ 20° C |
0.59 W/cm/°C |
Specific Heat |
0.31 J/g/°C |
Linear Expansion Coefficient @ 20° C |
5.7 x 10-6/°C |
Optical Properties |
|
Bulk Absorption @ 10.6 μm |
<0.03 cm-1 |
Temperature Change of Refractive Index @ 10.6µm |
408 x 10-6/°C |
