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Custom Calcite

calcite polarizer

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Knight Optical offers optical calcite that meets a wide array of application needs. Whether you’re in the market for calcite polarizers, calcite windows, calcite lenses, or calcite prisms, our range includes both off-the-shelf and custom optical calcite components for your specifications.

Optical calcite, also recognized as Iceland spar, is an anisotropic crystal, celebrated for being one of the most birefringent materials accessible today. This unique calcite optical property makes it a primary choice for polarizers, which are pivotal in various optical applications. Optical calcite can transmit over 75% in the 0.3-2.3µm range, making optical itcalcite an excellent choice for visible and NIR (Near-Infrared) applications.

Reach out to our multilingual technical sales team to discover how our high-quality optical calcite components and exceptional service can improve your instrumentation and supply chain experience.

calcite polarizer

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    Optical Properties and Metrology Testing

    Every optical calcite component supplied by Knight Optical undergoes testing by our highly skilled technicians in our state-of-the-art metrology lab. This ensures that each piece meets our high-quality standards, guaranteeing that your optical components deliver performance.

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

    Transmission Range0.3 to 2.3µm
    Refractive Index1.6654 @ 0.51µm
    Density2.71 g/cm3
    Melting PointDecomposes at 825°C
    HardnessKnoop 155, Mohs 3
    Diameter< 5mm to 50mm +
    Form error (@633nm)< 0.25 waves
    Centration/parallelism< 1 arc minute
    Scratch/dig< 20/10
    Typical coatingsBBAR @ 1-2.3µm

    Frequently Asked Questions

    Optical calcite, also known as Iceland spar, is a high-quality, clear variety of calcite known for its unique optical properties, including double refraction and birefringence. While regular calcite shares similar chemical compositions, optical calcite is specifically valued for its clarity and lack of internal structures, which allows for the manipulation of polarized light, making it ideal for various optical applications.

    The primary optical properties of calcite include double refraction, where a single light ray entering the crystal splits into two separate, polarized rays; birefringence, which is the difference in refractive indices in different crystal directions; and a high degree of transparency in the visible to near-infrared light spectrum. These properties make calcite invaluable in polarizing microscopes, optical systems, and specialized scientific equipment.

    Optical calcite is used in various optical systems and scientific research for its ability to polarize light. It is a key component in polarizing prisms like the Nicol and Glan-Taylor types, used in microscopes, lasers, and other optical instruments. Its unique birefringence properties are also utilized in fields such as geology, chemistry, and physics for studying the properties of light and materials.

    Optical calcite can be purchased from specialized optical component suppliers like us at Knight Optical. They offer high-quality optical calcite suitable for a wide range of applications, from academic research to industrial use. Knight Optical provides both standard and custom sizes and shapes, catering to specific customer needs and optical requirements.

    Iceland spar, or optical calcite, enhances polarized light applications by allowing only one of the two refracted light rays to pass through when aligned properly. This makes it an excellent material for improving the quality and effectiveness of polarized light used in scientific instruments, enhancing image contrast and resolution in microscopy, and improving the efficiency of polarizing prisms in optical devices.

    Yes, optical calcite components can be customized for specific optical devices. Customization can include specific dimensions, orientations, and surface coatings to enhance the calcite’s natural optical properties. Knight Optical offers bespoke services, working closely with customers to design and manufacture optical calcite components that meet precise specifications and application requirements, ensuring optimal performance in specialized optical systems.

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

    Additional Information


    Birefringence is when there are two distinct refractive indices of a material. This occurs when an unpolarised light beam enters the input surface of the material, it will be split into two polarised beams—the ordinary (o) and extraordinary (e) waves. Calcite’s o-and e-ray refractive indices are 1.6584 and 1.4864 respectively (@590nm).



    Calcite is very soft so it needs to be handled with care.


    Calcite is reactive to weak acids and can form carbon dioxide gas.


    It has a low solubility in water, but becomes more soluble as the water temperature increases.

    Typical Applications

    Aspherical Lenses for Laser Beam Shaping

    Polarising Prisms— Laser Applications

    Due to calcite’s transparency in the visible-NIR range and strong birefringence, it is an ideal material for polarisers. It can be highly polished to 20/10 scratch/dig on the input and output faces to minimise any scattering.

    Calcite can withstand a high damage threshold and can produce an exceptionally high polarisation purity from the output surface.

    Common polarising prisms include Rochon, Glan-Taylor/-Glan-Thompson/Glan-laser and Wollaston prisms.

    Retarder plates


    As calcite is a birefringent material it can be used to manufacture waveplates to alter the polarising state of the incident light.

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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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