Germanium (Ge)
High-index material optimized for mid-infrared wavelengths
Infrared Optical Material
Germanium is a high-refractive-index infrared material widely used in thermal imaging and long-wave infrared optics. Its high index enables compact lens designs, making it ideal for space-constrained systems. Germanium is opaque in the visible and relatively dense, which must be considered during system design.
Is this material right for your application?
Use When:
Avoid When:
Consider Alternatives:
Long-wave IR transmission is required
Compact optical designs are needed due to high refractive index
Thermal imaging systems operate in LWIR
Optical performance in the visible is not required
Environmental protection can be provided
Visible or near-visible transmission is required
Lightweight optics are critical
Uncoated surfaces will be exposed to harsh environments
Cost constraints outweigh optical benefits
ZnSe – lighter weight and easier handling
ZnS – multispectral or more durable window materials
Chalcogenide glass – alternative LWIR optical designs
Key Properties
Optical
Very high refractive index
Excellent LWIR transmission
Mechanical
Dense material
Moderate hardness
Environmental
Surface oxidation without coatings
Requires protective coatings
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Frequently asked questions about Barium Fluoride specifications and use-cases
FAQ
Q1. What wavelength range is Germanium used for?
Germanium operates in the infrared range from ~2 µm to ~14 µm.
Q2. Is Germanium suitable for thermal imaging?
Yes. It is widely used in thermal imaging and IR optics.
Q3. Is Germanium mechanically durable?
Germanium is hard but brittle and requires careful handling.
Q4. What are alternatives to Germanium?
Zinc Selenide (ZnSe) and Silicon.
High refractive index (~4.0).
Opaque in the visible spectrum.
Commonly AR-coated for IR systems.