Refractive Index ( absolute index of refraction )


The refractive index or index of refraction of a substance is a dimensionless number that describes how light, or any other radiation, propagates through that medium. The refractive index determines how much light is bent, or refracted, when entering a material. The refractive index of an optical medium is defined as the ratio of the speed of light in vacuum, and the phase velocity of light in the medium. The phase velocity of a wave is the rate at which the phase of the wave propagates in space. This is the velocity at which the phase of any one frequency component of the wave travels. For such a component, any given phase of the wave (for example, the crest) will appear to travel at the phase velocity.

Related formulas


nRefractive index (dimensionless)
cSpeed of light
vphThe phase velocity of light in the medium (m/s)