Name: 12.5mm Dia. x 1mm Thick, 3-12μm AR Coated, Ge Window
Brand: TECHSPEC
SKU: 83-347
Price: $235.00

Bevel:

Protective as needed

Clear Aperture (%):

90.00

Clear Aperture CA (mm):

11.25

Diameter (mm):

12.50 +0.0/-0.1

Thickness (mm):

1.00 ±0.1

Coating:

BBAR (3000-12000nm)

Coating Specification:

R_avg <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 n_d:

4.002 @ 11µm

Knoop Hardness (kg/mm²):

780

Parallelism (arcmin):

Poisson's Ratio:

0.28

Substrate: Many glass manufacturers offer the same material characteristics under different trade names. Learn More

Germanium (Ge)

Surface Flatness:

λ/10 @ 10.6μm

Surface Quality:

60-40

Type:

Protective Window

Wavelength Range (nm):

3000 - 12000

Young's Modulus (GPa):

102.7

Regulatory Compliance

RoHS 2015:

Compliant

Reach 223:

Compliant

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

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 that the transmission decreases as temperature increases. As such, these germanium 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.

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