What Are Wedge Prisms?
Wedge prisms are triangular prisms made of transparent material. Glass or plastic is used as the material. When parallel or laser beams are projected onto a prism, they are reflected or refracted.
Wedge Prisms, also known as Risley Prisms, are prisms with inclined optical surfaces.
Light entering wedge prisms is refracted toward the thicker side and is used to refract light at a special angle.
Uses of Wedge Prisms
Wedge Prisms are used to deflect light at minute angles. Declination is the angle created by the incident and emitted rays of light when they are refracted by a 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, either alone or in combination with other Wedge Prisms. Beam steering components are an integral part of many laser-equipped optical systems, including endoscopic laser scalpels.
Principles of Wedge Prisms
Wedge Prisms are prisms with one side inclined at a very small angle to the other side. Light entering Wedge Prisms is refracted in the direction of the prism’s thickness, which allows the light to be refracted at a special angle. This depends on the angle of the exit facet and typically deflects a beam incident on a perpendicular facet to an angle of 2° to 10°.
Rotating the wedge prisms with the laser as the source causes the trajectory to form a circle; using two wedge prisms, the light beam can be freely rotated and oriented in any direction relative to the incoming beam. It is also possible to double the amount of declination.
In addition, two Wedge Prisms can be used in combination to function as an anamorphic prism. Anamorphic prisms are used to convert an elliptical semiconductor laser beam into a nearly circular beam by changing the vertical and horizontal image magnification. Conversely, it is also possible to transform a circular beam into an elliptical beam.