Germanium is an excellent broadband Infrared (IR) window and substrate material. It has transmittance from 2.0 microns to 25 microns and with AR coatings has transmittance of an average of 70% and a peak of 92%.
- Transmittance from 2.0 μm to 25 μm
- Thickness: from 1 to 10 mm
- Dimensions up to 160 mm
| Thermal Properties: | |
| Thermal Expansion | 5.9 x 10-6 °C -1 @ 300K |
| Melting Point | 937°C |
| Thermal diffusivity | 0.36 cm2s-1 |
| Thermal conductivity | 0.58 W cm-1 °C-1 |
| Specific heat | 0.31 J g-1 °C-1 |
| Mechanical Properties: | |
| Young Modulus | 10.3x1011 dyn cm-2 @ 300K |
| Shear Modulus | 4.1x 1011 dyn cm-2 |
| Knoop Hardness | 780 kg mm-2 |
| Poisson constant | 0.26 |
| Electrical Properties: | |
| Di-electric constant | 16.2 |
| Resisitivity | 9.0 ohm cm |
| Optical Properties: | |
| Transmission | 2 - 14μm fino a circa 45° |
| Refractive Index | 4.025 @ 4μm 4.005 @ 10μm |
