Germanium windows/Optical Glass IR/Ge Glass Window Manufacturer

Germanium windows is an optical window which is opaque to UV and visible light but has a broad transmission range in IR. It has minimal chromatic aberration due to low dispersion, and we recommend using an anti-reflection coating because of its high index of refraction (4.0 from 2 – 14μm). Germanium has the property of thermal runaway, meaning that the transmission decreases as temperature increases. As such, Germanium windows should be used at temperatures below 100°C.

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 not suited for use in these conditions. Where weight is an issue, its relatively high density (5.327gm/cc) should be considered.
The Knoop Hardness of Germanium (780) is approximately twice that of Magnesium Fluoride, making it ideal for IR applications requiring rugged optics. Germanium’s high density (5.33 g/cm^3) should be considered when designing for weight-sensitive systems

Germanium windows are ideal for IR applications at a broad range of wavelengths, including use in lower-power CO2 lasers. Germanium also has low dispersion, ideal for imaging applications. The windows feature an AR coating providing high transmission from 3 to 12 µm.

We supply a wide range of anti-reflection coated germanium windows in a variety of shapes and sizes, both off-the-shelf and custom-made for your exact requirements.

1. Ideal for near-IR applications

2. Broadband 3 to 12 µm anti-reflection coating

3. Ideal for applications requiring low dispersion

4. Great for low-power CO2 laser applications