Europe, UK, Asia & RoW: [email protected] +44 (0)1622 859444 | USA & Canada: [email protected] +1 401-583-7846

My Cart

Germanium Window 25mmdia x 3mmthk AR/DLC 7-14um

SKU: WGE2533
More Information
pdf pdf
Diameter (mm) 25
Material Germanium
Coating AR/DLC 7-14um
Thickness (mm) 3
Coated Sides Both

Germanium (Ge) is a relatively hard, high-density, IR transmitting material that blocks UV and VIS wavelengths but allows IR from 2µm. Germanium has the highest refractive index of commonly available IR-transmitters and has low optical dispersion. This makes it desirable in aspects of lens design where its refractive index allows otherwise impossible specifications to be built. AR coating is recommended.

Germanium transmits over 45% between 2-14μm up to 45⁰C but transmission degrades slowly at 100⁰C then more rapidly above 200⁰C. Exposure to higher temperatures can lead to catastrophic failure in the material so Germanium is unsuitable for use in these conditions. Additionally, its relatively high density should be considered where weight is an issue. Germanium has a hardness of HK780, slightly higher than GaAs with which it shares similar mechanical properties.

Typical applications for Germanium include thermal imaging where the material can be used as a front optic while its index of refraction makes Germanium useful for wide-angle lenses and microscopes. Additionally, Germanium components can be used for FLIR (Forward Looking Infrared) and FTIR (Fourier Transformed Infrared) spectroscopy systems, alongside other analytical instruments.

Knight Optical stock a range of Germanium Windows DLC/AR coated for 7-12 µm, we can also offer custom Germanium windows to your specific requirement. Other Germanium components we can also offer are, Germanium lenses, Germanium prisms, and Germanium blanks to your specification for a range of applications. Every component is individually tested by our highly skilled technicians in our state of the art metrology lab to ensure all components meet our high quality standards



Surface Quality:

± 0.2mm
± 0.2mm
<1/10th wave at 10.6 micron
Parts with diameter to thickness ratio > 25:1 and uncoated parts not controlled
<60-40 scratch/dig
5 arcmin
Avg.T%>85% @7-14 micron*
Avg.T%>85% @3-12 micron*

*as measured on 1mmthk substrate

Mounting into cells.
Edging down to smaller sizes.

Uncoated material