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Custom Gallium Arsenide

Germanium optical components for Defence, Security & Aerospace industriesGallium Arsenide (GaAs) is a tough, IR transmitting, semi-insulating and insoluble material that shares many mechanical properties with Germanium. Gallium Arsenide is typically used where hardness and durability are desirable.

Below is a brief summary of gallium arsenide’s optical properties, a full data sheet is available here.

Transmission range

1 to 16µm

Refractive Index

3.2727 @ 10.33µm


5.315 g/cm3

Melting Point



Knoop 750

Knight Optical supplies high quality gallium arsenide components, including windows, lenses, and ground blanks, made to your custom specification. We can offer uncoated and coated optics, including broadband antireflective (BBAR) and diamond-like carbon (DLC) coatings. Our typical manufacturing specifications are listed below however we are always expanding our capabilities so if your requirements are not mentioned below, please contact our technical sales team who will guide you through your enquiry.


< 5mm to 50mm +

Form error (@633nm)

< 0.25 waves

Centration /parallelism

< 1 arc minute


< 40/20

Typical coatings

BBAR @ 1-14µm

DLC @ 1-14µm

With our in-house state-of-the-art metrology laboratory you can be confident that your optical components will meet your requirements. You can find out more about our testing facilities here.

Additional Information

  • Gallium arsenide is a very durable material. As well as its hardness of HK750, it is also chemically stable and non-hygroscopic.
  • It is diamond turnable which is beneficial for high precision spherical and aspheric lenses.
  • Like other semiconducting materials, gallium arsenide has an optical bandgap, though unlike germanium and silicon, it has a direct bandgap, with its intrinsic edge at 0.87µm.
  • Transmitting at around 40% between 2-15µm, with a low absorbance, a broadband antireflective (BBAR) coating can be applied to increase its spectral performance.

Typical Applications

Forward Looking Infrared (FLIR) systems
  • Gallium arsenide optics, including lenses and windows, are often used in FLIR systems due to their transmission in both the MWIR 3-5µm and LWIR 8-12µm wavebands as well as their durability.
CO2 Lasers
  • Gallium arsenide can be used in medium and high-powered CO2 lasers in place of zinc selenide, especially as a front optic due to its durability. However, unlike zinc selenide, it does not transmit in the visible region and can not be paired with a HeNe laser.
High-efficiency solar cells
  • GaAs is currently the most efficient material at converting solar energy to electricity. It  is sensitive to light so works well in low light and it has a good resistance to higher temperatures. Silicon solar cells are also commonly used as they are far more cost effective, but they do not have the same high efficiency.




Our 2022/2023 Catalogue

Inside Knight Optical’s catalogue you’ll find details of the industries we serve as well as the many other services we can offer. It also showcases hundreds of our most popular products, supported by useful technical information, to help you choose the right part for your application.
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