Germanium lenses product
Germanium lenses are optical lenses made of polished germanium. These lenses are rugged and resistant to corrosion, and are ideal for harsh environments and applications where there is constant exposure to the elements.
Our germanium lenses have a high refractive index—the highest refractive index among readily available IR transmitters. It also exhibits minimal chromatic aberration due to low dispersion. Because of these properties, Ge lenses are ideal for use in infrared (FLIR and FTIR) field applications. Other applications include thermal imaging systems and precision analytic instruments which may be used in harsh environments.
Germanium is also subject to thermal runaway. What this means is that the transmission will decrease as temperature increases, and the lens becomes opaque. Because of this thermal runaway effect, germanium lenses should only be used at temperatures below 100°C.
Germanium has optimal transmission (over 45%) in the 2-12 μm band, which makes it most useful for mid-infrared light. With anti-reflective coatings, transmission can be brought up to about 95%.
The types of Germanium Lenses include plano-concave, p-convex, concave-convex and aspheric germanium lenses.
Ebetter Optics manufactures quality germanium lenses in a range of popular sizes, from 5mm to 350 mm in diameter. Our standard anti reflective coating is best suited for light transmissions between 3 and 12 μm. The focal length of our lenses is determined up to a +/-1% tolerance, and the surface flatness is l/10 @ 633nm.
General specifications
| Substrate Material | Ge (Germanium) |
| Diameter | 5mm-350mm |
| Shape | Spherical Plano-Concave, Plano-Convex, Concave-Convex or Aspheric |
| Focal length | +/-1% |
| Surface Quality | 20-10 (after coating) |
| Surface figure | λ/10 @ 633nm |
| Clear Aperture | >90% of central dimension |
| Antireflection Coating | @ 3-12 um |
