Dove Prisms for Optical Image Rotation

Dove prisms are precision optical components used to rotate, invert, or retroreflect images. Designed as truncated right-angle prisms, they are ideal for applications involving collimated light. These prisms provide a unique optical effect: when rotated around their longitudinal axis, the output image rotates at twice the speed. For example, a 30° prism rotation results in a 60° image rotation.

Working Principle

When light enters through the sloped face and travels along the prism’s axis, it reflects off the bottom face and exits the opposite side, producing an inverted image. The single internal reflection ensures the image is flipped without lateral deviation or displacement. Total internal reflection (TIR) occurs even if the propagation and prism axes are not perfectly aligned, thanks to the high incidence angle.

If TIR cannot be maintained—such as when the hypotenuse isn't clean—we offer prisms with optional metallic or hydroelectric reflective coatings.

Material and Surface Specifications

• Materials Available: BK7 Grade A optical glass, Corning Fused Silica 7980, JGS1, JGS2

• Clear Aperture: >90%

• Dimension Tolerance: ±0.1 mm (tighter tolerance upon request)

• Angle Tolerance: <5 arc minutes

• Flatness: λ/4 @ 632.8 nm

• Surface Quality: 60-40 scratch and dig

• Coating: Available upon request

Geometry and Build

Dove prisms feature a long bottom reflective face with a sharp edge and a ground top surface. The overall length is about four times the height, which makes them optimal for collimated light but less suitable for converging beams due to potential astigmatism.

Understanding Optical Quality

Dimension Tolerance: Indicates the allowable size variation. Our standard is ±0.1 mm.

Angle Tolerance: Specifies the acceptable variation in angles, kept under 5 arc minutes for precision alignment.

Flatness: Deviation from an ideal flat surface; our standard is λ/4 at 632.8 nm.

Surface Quality (60-40): Guarantees no digs larger than 0.04 mm and no scratches longer than ¼ the diameter of the tested area. Scratches and digs affect surface performance, so our high polish ensures minimal scattering and distortion.

Applications

Dove prisms are widely used in optical systems requiring beam rotation or image manipulation, including:

• Astronomy

• Laser interferometry

• Pattern recognition

• Scientific instrumentation

They serve as image rotators in opto-mechanical assemblies, with a design originally developed by physicist Heinrich Wilhelm Dove (1803–1878).

Custom Specifications

For custom dimensions, coating options, or specific optical tolerances, please contact us directly. We offer OEM manufacturing and engineering support.