Germanium (Ge) Windows

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