refractive index

American  

noun

Optics.

1. index of refraction.

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refractive index British  

noun

1.  ν.   μ.  physics a measure of the extent to which radiation is refracted on passing through the interface between two media. It is the ratio of the sine of the angle of incidence to the sine of the angle of refraction, which can be shown to be equal to the ratio of the phase speed in the first medium to that in the second. In the case of electromagnetic radiation, esp light, it is usual to give values of the absolute refractive index of a medium, that is for radiation entering the medium from free space

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Etymology

Origin of refractive index

First recorded in 1830–40

Example Sentences

The resulting patterns show strong optical contrast because of the light-induced refractive index changes, making them easy to detect with optical methods.

From Science Daily • Apr. 21, 2026

The key difference in this new approach is the use of molybdenum diselenide, which has a much higher refractive index.

From Science Daily • Apr. 5, 2026

To tackle this challenge, researchers are actively exploring nanocomposites, integrating nanoparticles into the resin to boost its refractive index.

From Science Daily • May 9, 2024

In this case, the refractive index of the material, or how much light bends or deviates from its original path when is passes through, changed dramatically with atomic disorder.

From Science Daily • May 7, 2024

On the other hand, the divergence in some cases between the square of the optical refractive index and the dielectric constant was very marked.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" by Various