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Knight Optical(UK) Ltd - [email protected] - +44 (0)1622 859444

Germanium windows

What are you looking for in Stock?

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

Material: Germanium
+0, -0.2mm
± 0.2mm
Flatness: 1/10th wave at 10.6 micron (uncoated parts not toleranced)
Surface quality: <60-40 scratch/dig
Parallelism: 5 arcmin  
AR/DLC: Avg.T%>85% @7-14 micron*
AR/AR: Avg.T%>85% @3-12 micron*
  *as measured on 1mmthk substrate
  • Mounting into cells.
  • Edging down to smaller sizes.

Stock Optics

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Part No. Diameter
CoatingCoated SidesMaterial Price
WGE10011 Download 10010AR/DLC 7-14umBothGermanium £1,495.00
WGE5033 Download 503AR/DLC 7-14umBothGermanium £345.00
WGE5011 Download 5010AR/DLC 7-14umBothGermanium £575.00
WGE3200 323UncoatedNoneGermanium £102.60
WGE2502 25.41UncoatedNoneGermanium £39.10
WGE2500 251UncoatedNoneGermanium £39.10
WGE2501 252UncoatedNoneGermanium £55.00
WGE1000 102UncoatedNoneGermanium £21.70
WGE2533 Download 253AR/DLC 7-14umBothGermanium £145.00
WGE1211 Download 12.51AR/DLC 7-14umBothGermanium £100.00
WGE3033 Download 303AR/DLC 7-14umBothGermanium £195.00
WGE7533 Download 753AR/DLC 7-14umBothGermanium £545.00
WGE5014 Download 503AR/AR 3-12umBothGermanium £345.00
WGE1212 Download 12.51AR/AR 3-12umBothGermanium £100.00
WGE2511 251AR/DLC 7-14umBothGermanium £135.00
WGE2542 Download 251AR/AR 3-12umBothGermanium £135.00
WGE5012 Download 501AR/AR 3-12umBothGermanium £329.50
WGE2544 Download 253AR/AR 3-12umBothGermanium £145.00
WGE3001 301UncoatedNoneGermanium £39.10
WGE2911 29.511.71UncoatedNoneGermanium £66.50
WGE3002 302UncoatedNoneGermanium £70.90
WGE2985 29.58.51UncoatedNoneGermanium £63.60
WGE3005 300.5UncoatedNoneGermanium £31.80
wge1005 100.5UncoatedNoneGermanium £21.70
wge1601 161UncoatedNoneGermanium £31.80
wge2504 254UncoatedNoneGermanium £91.10
WGE2522 25.42UncoatedNoneGermanium £55.00
WGE1311 13110.3UncoatedNoneGermanium £53.50
wge2425 242.5UncoatedNoneGermanium £39.10
wge2505 250.5UncoatedNoneGermanium £31.80
wge1202 122UncoatedNoneGermanium £24.60
wge1803 183UncoatedNoneGermanium £39.10
wge1902 192UncoatedNoneGermanium £52.10
WGE2523 2523.51UncoatedNoneGermanium £59.30

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Our Multi-Lingual Sales Team are here to help with your requirments:

UK +44 (0)1622 859444
UK +44 (0)1622 850614
UK +44 (0)1622 851078
+1 401 583 7846

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