Prism

In optics, a prism is a transparent optical element by means of flat, polished surfaces that refract light. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use "prism" typically refers to this type. Some types of optical prisms are not in fact in the shape of geometric prisms. Prisms are characteristically made out of glass, but can be made from any material that is transparent to the wavelengths for which they are designed.A prism can be used to break light up into its constituent spectral colors (the colors of the rainbow). They can also be used to reflect light, or to split light into components with different polarizations.