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

A key concept behind this discovery is the refractive index, which describes how much a material bends or slows light.

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

The ensemble was excited by a linearly polarized green laser with a wavelength of 532 nanometers, and a high refractive index hemispherical lens was used to enhance the collection efficiency of the laser-induced fluorescence.

From Science Daily • Jun. 6, 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

This relation depends upon the refractive index of the material, but as most color stones are of somewhat similar refractive indices, the above proportions are sufficiently accurate for all.

From A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public by Wade, Frank Bertram