What is dove prisms?

Dove prisms are optical prisms that consist of two reflective surfaces that are at an angle of 90 degrees to each other. They are named after their inventor, H.W. Dove. These prisms are used to reflect an image through a specified angle without changing the image's orientation.

Dove prisms have an isosceles triangular shape, and the light entering the prism is refracted twice. The first refraction occurs at the angled side of the prism, where the light is deviated from the incoming path. The second refraction takes place when the light hits the opposite face, which reflects the light back towards the side from which it entered.

They are versatile and have several applications such as in photometry, interferometry, and in achromatic beam steering. They are used in polarimeters for measuring optical rotation angles, in autocollimators for alignment purposes, and as image rotators in optical systems.

Dove prisms are constructed from materials such as glass, calcium fluoride, and magnesium fluoride, which are transparent to the wavelengths of light being used. They are also available in various sizes and shapes to suit different applications.