A window with a substrate made of single-crystal germanium. Low absorption at the infrared region up to 20μm. With anti-reflective (AR) coating on the both faces, the product delivers superior transmission properties suitable for windows.





  • The AR-coated model offers high transmission properties for a wide range of light (3μm-5μm).
  • The product can be used as a window for specimen observation, laser irradiation, etc.

Typical Specifications


Model GEWI
Wavelength Range 3-10μm 5-9μm 2-13μm
AR Coating Y Y N
Reflectance < 4.0% < 2.0%
(One Side)
Size Φ25 x 1tmm, Φ30 x 1tmm
Substrate Single-crystal germanium
Parallelism Within 3 minutes
Scratch-Dig  60-40
Effective Diameter 80% of the actual diameter

Wavelength Characteristics of Reflectance(AR-coated_3-10μm)

Wavelength Characteristics of Reflectance(AR-coated_5-9μm)

Wavelength Characteristics of Reflectance(AR-uncoated)