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50.8mm Dia. x 3.0mm Thick, 3-12µm AR Coated, Ge Window

Germanium (Ge) Windows

Germanium (Ge) Windows

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Bevel:
Protective as needed
Clear Aperture (%):
90.00
Clear Aperture CA (mm):
45.72
Diameter (mm):
50.80 +0.0/-0.1
Thickness (mm):
3.00 ±0.1
Coating:
BBAR (3000-12000nm)
Coating Specification:
Ravg <5.0% @ 3 - 12µm
Coefficient of Thermal Expansion CTE (10-6/°C):
6.1
Density (g/cm3):
5.33
Edges:
Fine Ground
Index of Refraction nd:
4.002 @ 11µm
Knoop Hardness (kg/mm2):
780
Parallelism (arcmin):
<1
Poisson's Ratio:
0.28
Substrate: Many glass manufacturers offer the same material characteristics under different trade names. Learn More
Germanium (Ge)
Surface Flatness (P-V):
λ/10 @ 10.6μm
Surface Quality:
60-40
Type:
Protective Window
Wavelength Range (nm):
3000 - 12000
Young's Modulus (GPa):
102.7
Type of Window:
Crystal

Regulatory Compliance

RoHS 2015:
Compliant
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Certificate of Conformance:
View
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Reach 235:
Compliant
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Product Family Description

  • Uncoated or with AR Coatings Designed for a Variety of IR Ranges
  • Minimal Chromatic Aberration Due to Low Dispersion
  • Ideal for Infrared Applications Requiring Rugged Optics
  • DLC Coated Germanium Windows are also Available
  • Due to material supply chain disruptions with germanium, there may be increased lead times and price changes on our germanium products. For more information, please contact our customer service team.

TECHSPEC® Germanium (Ge) Windows are available off-the-shelf with three anti-reflection coating options: 3 - 5μm for mid-infrared applications, 3 - 12μm for broadband multispectral applications, or 8 - 12μm for thermal imaging applications. Due to its high index of refraction (around 4.0 from 2 - 14μm), an anti-reflection coating is recommended on these germanium windows for sufficient transmission in the region of interest. Germanium is subject to thermal runaway, meaning the transmission decreases as temperature increases. As such, TECHSPEC Germanium (Ge) Windows should be used at temperatures below 100°C. Germanium’s high density (5.33 g/cm3) should be considered when designing for weight-sensitive systems. The Knoop Hardness of germanium (780) is approximately twice that of magnesium fluoride, making it ideal for infrared applications requiring rugged optics. 

Technical Information

AR COATED GERMANIUM

Typical transmission of a 3mm thick Ge window with BBAR (3000-5000nm) coating at 0° AOI.

The blue shaded region indicates the coating design wavelengh range, with the following specification: 

Ravg <3% @ 3000 - 5000nm

Data outside this range is not guaranteed and is for reference only.

Click Here to Download Data

Typical transmission of a 3mm thick Ge window with BBAR (3000-12000nm) coating at 0° AOI.

The blue shaded region indicates the coating design wavelengh range, with the following specification: 

Ravg <5.0% @ 3 - 12μm

Data outside this range is not guaranteed and is for reference only.

Click Here to Download Data

Typical transmission of a 3mm thick Ge window with BBAR (8000-12000nm) coating at 0° AOI.

The blue shaded region indicates the coating design wavelengh range, with the following specification: 

Ravg <3.0% @ 8 - 12μm

Data outside this range is not guaranteed and is for reference only.

Click Here to Download Data