Germanium (Ge)
Crystal properties | ![]() |
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Crystal Type: | cubic, diamond structure | ||
Transmission Range | 1.8 ... 23 µm | ||
Refractive Index | 4.0034 @ 9.72 µm, 4.0028 @ 10.6 µm |
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Reflective Loss | 52.9 % @ 10 µm | ||
Density | 5.323 g/cm3 | ||
Melting Point | 956, 959, 942, 938 °C | ||
Molecular Weight | 72.59 | ||
Thermal Conductivity | 58.61 W/(m K) | ||
Specific Heat | 310 J/(kg K) @ 25 °C | ||
Thermal Expansion | 5.5×10–6 / K, 6.1×10–6 / K | ||
Hardness (Knoop) | 780 | ||
Young’s Modulus | 102.7 <100>, 155.3 <111> GPa | ||
Shear Modulus | 67 <100> GPa | ||
Bulk Modulus | 77.2 GPa | ||
Rupture Modulus | 93 MPa | ||
Elastic Coefficient: | C11 = 129 / C12 = 48.3 / C44 = 67.1 GPa | ||
Dielectric Constant | 16.6 @ f = 9.37 GHz | ||
Solubility in Water | Insoluble | ||
Application | Electronics lenses, band pass filters, thermography | ||
Remarks | laser damage threshold: 2.9 ...3.3 GW / cm2 | ||
Germanium substrates | ![]() |
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List of optical crystals |
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