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Right-Angle Prisms
Right Angle Prisms: Reliable Beam Bending and Image Control
Right angle prisms are among the most widely used optical components in imaging and beam steering systems. As the name suggests, these prisms feature a 90° angle between two of their faces, enabling precise light redirection and image manipulation with a compact and durable design.
Right angle prisms serve as key elements in laser systems, periscopes, telescopes, cameras, and optical instruments where light needs to be bent at 90° or 180°. Their versatility, ruggedness, and optical precision make them indispensable in both research and industrial environments.
How Right Angle Prisms Work
A standard right angle prism is a triangular block of glass (typically BK7 or fused silica) with one 90° angle and two 45° angles. Depending on how the prism is oriented, it can redirect light in several useful ways:
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90° Deflection Mode: Light enters one leg face, reflects off the hypotenuse via total internal reflection (TIR), and exits through the other leg face, turning the beam 90°.
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180° Retroreflection Mode: Light enters the hypotenuse, reflects internally off both legs, and exits back through the hypotenuse, sending the beam back parallel to the input (also known as the “roof” configuration).
Because of their shape and optical precision, right angle prisms can also be used to invert or rotate images, depending on orientation.
Applications of Right Angle Prisms
Thanks to their simplicity and flexibility, right angle prisms are found in countless optical systems:
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Laser Beam Steering: Used to bend or fold beams precisely in alignment-sensitive laser setups.
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Imaging Systems: Help manipulate image orientation in cameras, projectors, and optical scopes.
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Periscopes and Telescopes: Redirect the line of sight around obstacles while maintaining image quality.
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Fiber Optic Coupling: Aid in aligning beams into or out of optical fibers.
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Industrial Metrology: Used in interferometers and inspection systems to control light paths.
Their solid glass construction and alignment-free design also make right angle prisms more robust and easier to integrate than mirrors in many situations.
Design Variants and Coatings
Right angle prisms come in multiple variations to suit specific application needs:
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Uncoated (TIR-Based): Rely on total internal reflection for beam redirection, ideal for clean, dry environments.
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Metal-Coated Hypotenuse: Used when the angle of incidence is too shallow for TIR or when operating in non-ideal conditions.
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Dielectric Coated: Provides high reflectivity at specific wavelengths with minimal absorption.
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Cemented Pairs (RAP Assemblies): Two prisms joined for more complex beam manipulation.
When selecting a prism, consider wavelength range, optical material, surface quality, dimensional tolerance, and coating type to match your system requirements.
Explore Right Angle Prisms on FindLight
Whether you're folding a laser beam or adjusting your imaging system, right angle prisms offer dependable performance with minimal fuss. FindLight offers a curated selection from top vendors, complete with datasheets, specs, and direct quote options.
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