» Germanium (Ge) Crystals
Germanium (Ge) is used widely for lenses and windows in thermal imaging and FLIR applications .lts high index of refraction makes it of particular intrest. Useful tansmison range of Germanium windows is from 2to 12 m. Germanium is opaque in the visible.
Germanium has the property of thermal runaway, meaning that the transmission decreases as temperature increases. As such, Ge window should be used at temperatures below 100C. The higher Knoop Hardness of Germanium (780) makes it ideal for IR applications requiring rugged optics. Germanium's high density
(5.33g/cm^3) should be considered when designing for weight-sensitive systems.
| Material Properties： |
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| Material type | N or P |
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| Crystal direction | [100] [111] |
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| Resistivity（ohm/cm） | 4-50 |
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| Thermal Conductivity J/k .m.s | 58.61@293k |
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| Density（g/cm3） | 5.33 |
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| Melting Point | 1410℃ |
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| Thermal Expansion Coefficients(1/℃) | 6.1X10-6@298k |
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| Knoop Hardness | 780 |
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| Absorption Coefficient | 3x10-2@10600nm |
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| we can provide different dimension prism，window，mirror，wedge and lens at present. |
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| Plano Product Capability |
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| Attribute | Commercial | High Precision |
| Orientation | 士0.5° | 士0.2° |
| Dimension Tolerane | 士0.1mm | 士0.01mm |
| End-faces Configuration | Flat |
| Surface Quality | 40-20 scratch and dig | 10-5 scratch and dig |
| Flatness | λ/4 | λ/10 |
| Parallelism | 20" | 2" |
| Perpendicularity | 15′ | 5′ |
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| Plano Product Detail specs： |
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| Type | Polishing Area | Roughness |
| Thick plate | ≤5X5mm | 1nm |
| 5X5mm--8x8mm | 1nm |
| 8x8mm---φ38mm | 1nm |
| Thin plate | ≤5X5mm | 1nm |
| 5X5mm--8x8mm | 1nm |
| 8x8mm---φ38mm | 1nm |
