Silicon Lens(Si lens) for Infrared Applications

Silicon Lens(Si lens) for Infrared Applications

Wavelength infrared provides silicon lens in popular sizes from 10mm to 200 mm in diameter. Lens size over 200mm could also be provided upon request. Our standard AR and DLC coating are best suited for band in 3-5 micron. The focal length of our lenses would be controlled to up to +/-1% tolerance, surface flatness λ/4 @ 632.8nm and surface irregularity less than 0.5 micron.

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Silicon lens is optical lens made of silicon. Silicon (Si) is a crystalline material that is commonly used in infrared optical systems operating in the 3 to 5µm spectral band. Its refractive index is near 3.4 throughout the range. It has comparatively low densities between common infrared materials, which is only half that of Ge, GaAs and ZnSe. Thus silicon material is ideal choice for system with weight concerns. Silicon is also harder and cheaper than most of the common infrared materials, reduce the material cost while increase the fabrication cost at the same time.

Silicon is well suited for MWIR application but due to the strong absorption above 6 micron, it is not suited for LWIR application. It could also be used as a mirror substrate for laser application due to its thermal conductivity, light weight, and hardness.

Wavelength Infrared can manufacture a variety shape of silicon lens with plane, concave, convex, aspheric and diffractive surfaces. Silicon is most popular for systems operating in the 3-5µm spectral region, with anti-reflective coatings (AR coating), the average transmission could be brought up to 98%. We can also apply diamond-like carbon coating (DLC coating) or high durable coating (HD coating) on lens surface to provide extra protection against scratch and impact.

Wavelength infrared manufactures quality custom spherical and aspheric silicon lens. They can either focus or diverge incoming light beam to meet specific requirement of the infrared system.


Material Silicon(Si)
Diameter 10mm-300mm
Shape Spherical or Aspheric
Focal length +/-1%
Decentration <1’
Surface figure <λ/4 @ 632.8nm (Spherical surface)
Surface irregularity < 0.5 micron (Aspheric surface)
Clear Aperture >90%
Coating AR or DLC


1.DLC/AR coating is available upon request.

2.Customization available for this product to suit your technical requirements. Let us know your required specifications.

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    Wavelength has been focused on providing high precision optical products for 20 years