These prisms (corner cube) have 3 mirror surfaces making angles of 90° to each other, juxtaposed to form the corner of a cube with the entrance face perpendicular to cube diagonal. All beams, despite of incident direction, are reflected back to the original direction. Solid corner cube is used in high precision applications or with lasers over very long distances. These ”angle insensitive” mirrors therefore find frequent applications in situations where orientation is difficult or impossible to control and where a mirror would therefore be unsatisfactory.
Deviate incident light by 180 degrees independently of an angle of incidence