index of refraction


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index of refraction

1. The ratio of the angle made by the incident ray with the perpendicular (angle of incidence) to that made by the emergent ray (angle of refraction).
2. The ratio of the speed of light in a vacuum to its speed in another medium. The refractive index of water is 1.33; that of the crystalline lens of the eye is 1.413.
Synonym: refractive index
See also: index

index of refraction

A measure of the optical density of a transparent material such as glass or the cornea. It is the ratio of the speed of light through the material to its speed in a vacuum.

Index of refraction

A constant number for any material for any given color of light that is an indicator of the degree of the bending of the light caused by that material.

index of refraction

The ratio of the speed of light in a vacuum or in air, c, to the speed of light in a given medium, v. Symbol: n. Hence,
n = c/v
The speed of light in a given medium depends upon its wavelength. Consequently, the index of refraction varies accordingly, being greater for short wavelengths (blue) than for longer wavelengths (red). The index of refraction forms the basis of Snell's law, which quantitatively determines the deviation of light rays traversing a surface separating two media of different refractive indices. Syn. refractive index. Plural: indices. See dispersion; law of refraction; gradient-index lens; high index lens; speed of light; refractometer.
Table I3 Refractive indices of some transparent media at selected wavelengths
spectral lineGFDCA
OriginCalciumHydrogenSodiumHydrogenOxygen
wavelength (nm)430.8486.1589.3656.3759.4
aqueous or vitreous humour1.34401.34041.33601.33411.3317
crystalline lens1.43071.42591.42001.41751.4144
spectacle crown1.53481.52931.52301.52041.5163
dense flint1.63971.62901.61701.61221.6062

Table I4 Index of refraction n of various media for sodium light (λ = 589.3)
air1.00
water (at 20ºC)1.333
spectacle crown glass1.523
flint glass (dense)1.62
flint glass (extra dense)1.65-1.70
titanium oxide glass1.701
calcite crystal
ordinary ray1.658
extraordinary ray1.486
quartz crystal
ordinary ray1.544
extraordinary ray1.553
diamond2.42
Canada balsam1.53-1.54
CR-391.498
polycarbonate1.586
silicone rubber1.44
CAB1.47
PMMA1.49
HEMA1.43
hydrogel polymer
20% water content1.46-1.48
75% water content1.37-1.38
eye
tears1.336
cornea1.376
aqueous humour1.336
crystalline lens (average effect)1.42
vitreous humour1.336
References in periodicals archive ?
In that spirit, we will present the design and results of an experiment that proves that an index of refraction greater than 1 does not give non-null results in Michelson-interferometer experiments as Cahill asserts.
The parameters include the microsphere diameter, real part of the index of refraction, imaginary part of the index of refraction, the microsphere concentration, and the instrument acceptance angle.
To calculate the index of refraction of the unknown sample, one needs a very exact knowledge of the index of the glass body.
It is visible for the same reasons in liquids that have a different index of refraction from its own.
They don't require a mode conditioning patch cord, since the fiber index of refraction profile contains virtually no anomalies or center line dip.
This offset is required because differential mode delay, or multiple overlapping signals, can occur when a single-mode signal is launched into the area of a multimode core that contains a dip in the index of refraction.
Brewster's photoelasticity law states that the index of refraction in a strained material becomes directional.
It turned out that the speed of light through any transparent medium is equal to the speed of light in a vacuum, divided by the index of refraction of the medium.
It does not suffer from the Christiansen effect (band distortion from changes in index of refraction in regions of an absorption band) observed when using KBr pellets and mulls.
This is in contrast to traditional lenses, like those found in optical telescopes and microscopes, which use their surface shape or single index of refraction to bend light one way or another.
These are the artificial materials exhibit the properties that are not available in nature, such as backward propagation, negative index of refraction and so on.

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