Optical parts 101: Wedge Prism
A prism is a triangular prism made of a transparent material. Glass or plastic is used as the material. When a parallel beam or laser beam is applied to a prism, it is reflected or refracted.
Wedge prisms, also known as risley prisms, are prisms with tilted optical surfaces. Normally, one side is tilted at a very small angle with respect to the other side.
The light that enters the wedge prism is refracted toward the thicker side, so it is used when refracting light at a special angle.
Usage of wedge prism
Wedge prisms are used in applications that declinate (deflect) light to minute angles. The deviation angle is the angle created by the incident and emitted rays in the refraction of light by the prism, and it depends on the apex angle of the prism (the angle facing the base of the triangle) and the refractive index.
It can be used for beam steering by itself or in combination with other wedge prisms. Beam steering components are an integral part of many laser-mounted optical systems and are also used in endoscopic laser scalpels and the like.
Wedge prism principle
A wedge prism is a prism in which one side is tilted at a very small angle with respect to the other side. The light that enters the wedge prism is refracted in the thicker direction of the prism, allowing it to be refracted at a special angle. This depends on the angle of the exit surface and typically deflects the beam incident on the right angle surface to an angle of 2 ° to 10 °.
When you rotate the wedge prism using a laser as a light source, the trajectory draws a circle. With two wedge prisms, you can rotate the light beam freely and orient it in any direction with respect to the input beam. It is also possible to double the amount of declination up to.
Also, by using two wedge prisms in combination, it can function as an anamorphic prism. Anamorphic prisms are used to change the vertical and horizontal image magnification of an elliptical semiconductor laser beam to convert it into a nearly circular beam. Conversely, it is also possible to convert a circular beam into an ellipse.

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