Germanium (Ge)
OpticsLand™ manufactures precision Germanium optical
components, which are widely used for infrared applications. Its useful transmission range
is from 1.8m m to 17m m. Due to wide
transmission range and opaque in visible Ge is well suited for manufacturing of optical
components for IR applications in lasers and optical systems. Its high index of refraction
(greater than 4) makes it of particular interest for lens design.
Germanium absorption increases with temperature. At 2000C it becomes non - transmissive.
Germanium components are used with AR coatings because of high surface reflectivity of
substrate.
Physical Properties
| Crystal type | cubic |
| Lattice constant | a=5.657Å |
| Density | 5.33g/cm3 |
| Melting point | 937°C |
| Refractive index | n=4.0034 @ 10.6 mm |
| Transmission band | 1.8 - 17 mm |
General Specifications of Germanium Optical Components
| Material | optical quality Ge Dn/cm < 0.5*10-5 |
| Surface Quality | 60-40 scratch & dig |
| Clear aperture | 80% of diameter |
| Diameter tolerance | +0.0, -0.1 mm |
| Thickness tolerance | +1.0, -0.1 mm |
| Flatness | <1.5 l per inch @ 633 nm |
Ge Windows |
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Diameter, mm |
Thickness, mm |
Coating |
Cat.-No |
Price |
| 25.4 | 3.0 | AR/AR @ 10.6 mm |
40801 | $139 |
| 38.1 | 4.0 | 40802 | $199 |
|
| 50.8 | 5.0 | 40803 | $279 |
|
| 25.4 | 3.0 | uncoated | 40811 | $99 |
| 38.1 | 4.0 | 40812 | $159 |
|
| 50.8 | 5.0 | 40813 | $199 |
|
Germanium lenses, Brewster windows, mirrors and beamsplitters are available on request.
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