total internal reflection

total internal reflection

Complete reflection of a ray of light in a medium such as water or glass, from the surrounding surfaces back into the medium. It occurs when the angle of incidence is greater than a certain limiting angle, called the critical angle. In general, it takes place at the boundary between two transparent media when a ray of light in a medium of higher index of refraction approaches another medium of lower index of refraction at more than the critical angle. At all angles less than the critical angle, both reflection and refraction occur. Total internal reflection is responsible for rainbows, atmospheric halos, the sparkle of a diamond, and the path of light through optical fibres.

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total internal reflection

Light that is reflected back from the edge of the medium it is traveling through. When light rays travel at an angle greater than the "critical" angle, which is determined by the medium, the light reflects back into the medium. When they are less than the critical angle (more perpendicular), the light is refracted out of the medium and lost to the outside. See refractive index.

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total internal reflection [′tōd·əl in′tərn·əl ri′flek·shən]

(optics)

A phenomenon in which electromagnetic radiation in a given medium which is incident on the boundary with a less-dense medium (one having a lower index of refraction) at an angle less than the critical angle is completely reflected from the boundary.