Germanium – Ge

lenses, windows, mirrors, filters and prisms


Germanium lenses have a high refractive index making it essential to add anti-reflection coating to improve its transmission.

Germanium windows and lenses are highly sensitive to temperatures above 70°C when it will become opaque. Germanium has a rugged appearance and is especially durable making it suitable for external Infrared applications.

Our Germanium lenses are most commonly used to focus infrared light and can be used for camera lenses. 


Transmission Range 1.8 – 23.0 µ
Crystal Structure Diamond
Cleavage Plane 111
Colour Metalic lustre
Density 5.327 (25°)
Melting Point (°) 942
Reflection Loss 52.9% (10µ) for 2 surfaces
Solubility index Insoluble
Hardness (Knoop) 692
Thermal Conductivity (cal/cm sec°C) 0.14 (20°C)
Thermal Expansion coefficient (/°C) 5.5×10-6(25°C)

Read more about Geranium here.

Germanium (Ge) windows and Germanium (Ge) lenses

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