Right angle prism uses critical angle characteristic. Efficient internal total reflection of incident light is one of the basic functions of right-angle prism
It comes with or withou coating
A Right Angle Prism is used to turn or deflect a beam through 90° or 180°. In either case this is achieved by total internal reflection and produces a very efficient broadband reflector.
It is important that the incoming beam is collimated and enters the prism at a normal angle of incidence. This is so that total internal reflection can be achieved.
