Dove Prism

Dove Prism

Dove prisms  It resembles half of a common right-angle prism in which a ray entering parallel to hypotenuse face is reflected internally at that face and emerges parallel to its incident direction. One of the incident rays emerges along a continuation of its incident direction, and if the prism is rotated about that ray through some angle, the image rotates through twice that angle. A Dove Prism must be used in parallel light.

What Is a Dove Prism?

A Dove prism is a type of optical prism used to rotate, invert, or retroreflect an image. It has a unique shape—similar to a right-angle triangular prism with its top truncated.

These prisms are most effective when used with collimated light. Because the prism's length is roughly four times its height, using it with converging light can introduce significant astigmatism.

When light enters through the slanted face and travels along the prism’s longitudinal axis, it reflects once off the bottom (flat) surface and exits through the opposite short side. This results in an inverted image. One of the most unique features of a Dove prism is that when the prism is rotated around its longitudinal axis, the image inside rotates at twice the speed. For example, rotating the prism by 30° will rotate the image by 60°.

Thanks to this property, Dove prisms are widely used to rotate beams of light to precise angles. While the image is flipped vertically, there is no lateral shift or angular deviation, since only a single internal reflection occurs.

Even if the light’s path is not perfectly aligned with the prism’s axis, the steep angle of incidence ensures total internal reflection (TIR) on the bottom surface. However, in applications where the hypotenuse surface may not remain clean enough for reliable TIR, metallic or dielectric coatings can be applied to maintain performance.

Custom Coatings

We offer custom coating services for uncoated prisms upon request. Available spectral ranges include:

245–400 nm (-UV)

350–700 nm (-A)

650–1050 nm (-B)

1050–1700 nm (-C)

Dove Prism Manufacturing

We follow a step-by-step process and conduct rigorous quality checks throughout the process. 

Optical Design: Work with our engineers to validate your print or rely on our expertise to get your design just right. We'll recommend the right optical material and send it off to production.

Crown and flint fabrication: we'll use materials with lower dispersion for convex crowns and higher dispersion materials for concave flints.  

Optical alignment and assembly: After the optical and mechanical axes have been accurately aligned, the lenses are bonded together using specialised refractive index optical adhesives. UV-cured optical adhesive is then used.

Centring: After assembly, some doublet lenses are centred to their final diameter, while others are pre-centred before gluing. After assembly, the bimodal lenses can also be darkened to reduce scattering, which is useful in some optical applications. 

Tests and Measurements: Interferometry, surface roughness, radius of curvature, aberration, etc. 

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