Light guide

A light guide is able to guide light through total reflection within a transparent material.
It typically consists of a thinner core, the material of which has a higher refractive index than the surrounding material.
When light enters the core of the light guide, it is total reflected on the interface between the core and the coat and remains bound within the core, which means that it can be guided over a longer route.
Light guide is typically used in telecommunications and lighting technology.