|
We produce:
Contact Sales Team for pricing for custom size and coatings requirements. We offer very competitive prices on Germanium optics! Check now!
Alkor is one of the largest manufacturers of Germanium optics with 25 years experience. Our Germanium windows, wedges and lenses are widely used in IR sensors, LIDARs, thermal image and medical applications, in pyrometry and thermography, IR cameras all over the world.
Uncoated Germanium transmission curve. Window thickness 10mm.
Germanium is used widely for lenses and windows in thermal imaging, FLIR applications, as germanium viewports. Its high index of refraction (about 4) makes it of particular interest
Useful transmission range of Germanium windows is from 2 to 13µm. Germanium is opaque in the visible. Germanium has the property of thermal runaway, meaning that the transmission decreases as temperature increases. As such, Germanium window should be used at temperatures below 100°C.
The Knoop Hardness of Germanium (780) is approximately twice that of Magnesium Fluoride, making it ideal for IR applications requiring rugged optics. Germanium’s high density (5.33 g/cm^3) should be considered when designing for weight-sensitive systems.
Custom germanium windows and germanium lenses are available in any size and configuration. Anti-reflection coatings can be applied for 2-14µm, 3-5µm, 8-12µm (BBAR coating or DLC/AR) depending on your custom application. Ask managers for transmission curves.
AR/AR coating for 8-12microns.
AR/AR coating for 3-12microns.
| Germanium properties |
| Chemical Formula |
Ge |
| Crystal Form |
Monocrystal, orientation <111>, N-type |
| Crystal Class |
Cubic |
| Resistivity, Ohm*cm |
5-40 |
| Lattice Constant, Å |
5.66 |
| Molecular Weight |
72.60 |
| Density, g/cm3 at 300 K |
5.33 |
| Dielectric Constant for 9.37 x 109 Hz at 300 K |
16.6 |
| Melting Temperature, K |
1210 |
| Thermal Conductivity, W/(m K) at 293 K |
59 |
| Thermal Expansion, 1/K at 298 K |
6.1 x 10-6 |
| Specific Heat, cal/(g K) at 273-373 K |
0.074 |
| Debye Temperature, K |
370 |
| Bandgap, eV |
0.67 |
| Solubility in water |
None |
| Knoop Hardness, kg/mm2 |
800 |
| Mohs Hardness |
6.3 |
| Young's Modulus, GPa |
102.66 |
| Shear Modulus, GPa |
67.04 |
| Bulk Modulus, GPa |
77.86 |
| Poisson's Ratio |
0.278 |
| µm |
No |
µm |
No |
µm |
No |
| 2.058 |
4.102 |
2.153 |
4.0919 |
2.313 |
4.0786 |
| 2.437 |
4.0708 |
2.577 |
4.0609 |
2.714 |
4.0562 |
| 2.998 |
4.0452 |
3.303 |
4.0369 |
4.258 |
4.0216 |
| 4.866 |
4.017 |
6.238 |
4.0094 |
8.660 |
4.0043 |
| 9.720 |
4.0034 |
11.04 |
4.0026 |
12.00 |
4.0023 |
| 13.02 |
4.0021 |
|
|
|
|
See Also: Silicon optics; ZnSe optics
|
