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Custom Gallium Arsenide

scaled gallium arsenide lens

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Knight Optical is a provider of gallium arsenide optical components specifically for the Defence, Security, and Aerospace industries. Gallium Arsenide (GaAs) is recognized for its IR transmitting, semi-insulating properties, and insolubility, which makes it an ideal choice for applications requiring durability and high-performance optical properties.

We specialize in supplying top-quality gallium arsenide optics, including gallium arsenide lenses, gallium arsenide windows, and gallium arsenide ground blanks designed to meet your specific requirements. Whether you’re looking for gallium arsenide optics with broadband antireflective (BBAR) coatings, diamond-like carbon (DLC) coatings, or uncoated options, Knight Optical can cater to your needs. Our gallium arsenide optics stock is created to achieve the best optical absorption and transmission qualities, ensuring that your optical components deliver exceptional performance.

scaled gallium arsenide lens

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    Optical Properties of Gallium Arsenide

    The gallium arsenide refractive index and optical absorption are key factors we consider to improve the performance of your optical systems. What sets our gallium arsenide optical fiber and other GaAs products apart is not just their optical properties, but also the assurance of quality and precision backed by our in-house state-of-the-art metrology laboratory. This guarantees that your gallium arsenide components will meet the requirements of your projects.

    If you’re curious about the optical transmission of gallium arsenide, contact our technical sales team, who are here to guide you through the specifications and how our products can meet your application needs. You can find out more about our testing facilities here.

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

    Transmission Range1 to 16µm
    Refractive Index3.2727 @ 10.33µm
    Density5.315 g/cm3
    Melting Point1511°C
    HardnessKnoop 750
    Diameter< 5mm to 50mm +
    Form error (@633nm)< 0.25 waves
    Centration/parallelism< 1 arc minute
    Scratch/dig< 40/20
    Typical coatingsBBAR @ 1-14µm, DLC @ 1-14µm

    Frequently Asked Questions

    Gallium arsenide (GaAs) is a compound semiconductor material known for its excellent optical and electronic properties. Key optical properties include a high refractive index, low optical absorption in the infrared range, and strong optoelectronic conversion efficiency. These characteristics make GaAs highly suitable for use in various optical components such as lenses, windows, and in the cores of optical fibers, especially in telecommunications and infrared applications.

    Gallium arsenide optics are used in modern optical systems primarily for their infrared transmission capabilities and electro-optical applications. They are integral in devices such as infrared cameras, laser diodes, and photodetectors. GaAs lenses and windows are particularly valued in systems requiring high resistance to thermal shock and low dispersion in the IR spectrum.

    The cost of gallium arsenide components is influenced by factors such as the purity of the material, the complexity of the component’s design, and the precision required for the optical application. Additionally, the overall demand and supply in the semiconductor market can affect GaAs prices. Despite being more expensive than traditional optical materials, GaAs is often selected for its superior performance in specific applications.

    The refractive index of gallium arsenide is approximately 3.3 at 1 µm (1000 nm) wavelength, though this value can vary slightly depending on the wavelength of light being used. This high refractive index makes GaAs effective for creating highly efficient lenses and optical components, particularly for infrared and near-infrared applications.

    The optical transmission range of gallium arsenide typically extends from about 1 to 17 µm (micrometres), covering a significant portion of the infrared spectrum. This wide transmission range makes GaAs ideal for infrared optics, allowing for the creation of components that operate efficiently across various IR applications, including thermal imaging and spectroscopy.

    The optical absorption coefficient of GaAs varies significantly with wavelength but is generally low in the infrared region, making it an excellent material for transmitting IR light. At wavelengths where GaAs is transparent, the absorption coefficient can be minimal; however, it increases sharply at wavelengths shorter than the material’s bandgap (approximately 0.9 µm). The exact value at specific wavelengths is critical for designing optical components like photodetectors and solar cells, where understanding light absorption rates is essential for optimizing performance.

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    We are ready and waiting to answer any queries you may have about gallium arsenide.

    Additional Information


    Gallium arsenide is a very durable material. As well as its hardness of HK750, it is also chemically stable and non-hygroscopic.


    Gallium arsenide is diamond-turnable, which is beneficial for high-precision spherical and aspheric lenses.

    Semiconducting Materials

    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

    Infrared Lenses for FLIR Thermal Imaging

    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.

    Infrared Lenses for Low Powered CO2 Lasers

    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.

    Gallium Arsenide for High-efficiency Solar Cells

    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 scenarios. Further, it has 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.

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    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.

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