Anamorphic Prism

Anamorphic prism is a pair of prisms which is usually used for reshaping the profile of a laser beam. For example, the elliptical beam from a laser diode can be transformed into a beam with circular cross-section, as is needed for many applications, by using an optical prism pair as a beam expander for only one direction (e.g., the horizontal one). Of course, one can also just modify the ellipticity, or convert a circular beam into an elliptical one.