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Corner Cube Prisms

Author: the photonics expert Dr. Rüdiger Paschotta (RP)

Definition: prisms with three reflecting surfaces which act as retroreflectors

Alternative terms: corner cubes, retroreflecting prisms, trihedral prisms

More general term: prisms

Category: article belongs to category general optics general optics

DOI: 10.61835/fjn Cite the article: BibTex plain text HTML Link to this page! LinkedIn

Corner cube prisms are prisms which act as corner reflectors, a type of retroreflectors. The basic operation principle is that there are internal reflections on three mutually orthogonal prism surfaces, leading to a direction of a reflected beam which is nominally parallel to the direction of the incident beam – with the accuracy limited only by the accuracy of the surface orientation of the prism. Precision prisms can offer excellent parallelism of incoming and reflecting beams. It is usually specified as an angular deviation, e.g. < 2 arcseconds.

The operation principle is illustrated in Figure 1 for a device which works only in one plane and involves two reflections. A tilt of the prism around one axis can still modify the direction of the reflected beam. Only by using three such reflections, that can be avoided.

Figure 1: A prism retroreflector working in one plane only. Even with some tilt of the prism around an axis perpendicular to the drawing plane, the direction of the reflected beam is not changed.

Typically, one utilizes total internal reflection on the mentioned three surfaces, or alternatively reflections on metalized surfaces.

Of course, the retroreflection works properly with a laser beam only when it fully hits one of the reflecting surfaces; it should not be directed into the corner.

Despite the name containing the term “cube”, corner cube prisms are generally not having the geometric form of a cube. Instead, the input/output side is oriented roughly perpendicular to the direction of incoming beams, and opposite to it there is the “corner” formed by three mutually perpendicular surfaces. The exact orientation of the input/output surface is not critical, but it is easier to have an effective anti-reflection coating when the incidence is roughly perpendicular. Usually, the input/output surface is equipped with a broadband AR coating. Imperfect operation of the coating leads to a parasitic reflected beam.

Corner cube prisms may be supplied as bare prisms, or together with holds for mounting e.g. to a surface. They are often used in the context of optical metrology, e.g. in interferometers, and in spectroscopy.

More to Learn

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Suppliers

The RP Photonics Buyer's Guide contains 17 suppliers for corner cube prisms. Among them:

Artifex Engineering

Artifex offers custom corner cube prisms tailored to your requirements, which can be either solid or hollow. Our retroreflectors are available in a range of substrates and coatings and can be mounted on request. Visit our product page for more information. We look forward to your inquiry.

Shalom EO

Shalom EO has developed a capable production workshop that could offer various kinds of custom and off-the-shelf corner cube prisms made of N-BK7, UV fused silica, and other custom materials with diverse coating options like silver/gold coatings, and coatings in the visible, UV, and NIR spectrum.

Shalom EO's main types of corner cube retroreflectors include:

Standard corner cube retroreflectors of routine choices.
Truncated corner cube reflectors of lightweight and compact dimensions.
Lateral transfer corner cube retroreflectors with one trihedral reflecting face at one terminal of the prism and two trihedral reflecting faces forming a roof edge at the other end are designed for applications requiring a lateral beam displacement.
Customized hollow corner retroreflectors that perform great in low-pressure conditions and mitigate the aberrations derived from glass dispersion and temperature fluctuations.

Sinoptix

We offer on-demand manufacturing of corner cube prisms / retroreflector prism. N-BK7 or HK9L substrate, with high reflective silver or aluminium coating and can reach precision down to 2" of deviation.

Avantier

A corner cube prism, also known as a retroreflector, a CCR, or a trihedral prism, is an optical prism that sends an incoming beam of light directly towards its point of origin while translating it spatially.

Shanghai Optics

Shanghai Optics Inc. custom corner cube prisms are used for applications in spectroscopy, satellites, or battlefield technology, also in land surveying, laser resonator cavities, electronic distance measurement, and space vessel docking.

EKSMA OPTICS

EKSMA Optics offers a selection of corner cube prisms for quick delivery. Custom metal or dielectric coatings can be applied on request.

Knight Optical

Knight Optical offer precision N-BK7 corner cube prisms with a 3 arcsecond deviation angle. Often used for beam steering, these retroreflector prisms are also available as custom orders including mounted options.

Edmund Optics

Edmund Optics offers mounted and unmounted retroreflection prisms in a range coating options. Reflective surfaces are available with reflection coatings including aluminum and silver. Entrance surfaces are available with VIS 0° anti-reflection coatings. Due to their complex shape, mounting a retroflection prism can be difficult. To ease system integration, mounted retroreflection prisms featuring ¼-20 tapped holes are available.

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