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 ?
Hence, according to (22), the index of refraction depends on the position (r).
1: The change for the index of refraction of the vacuum (n-1) versus the temperature of the superconductor (T).
depending on [sigma], such that there exists an interior transmission eigenvalues of the index of refraction n', in [sigma]-neighborhood of each [k.sub.j], whenever [eta] is small enough.
[13] Austin RW, Halikas G (1976) The Index of Refraction of Seawater, Vol.
Beyond the limitations related to the RTE itself, one can blame the imprecision of several of the input parameters such as the pigments' index of refraction, their size, and shape distributions or the reflection coefficients at the air/film and film/substrate interfaces.
The square of the index of refraction with the addition of nonlinear terms becomes
Index of refraction in the terahertz frequency range for composite was measured using a reflection and transmission configuration.
(d) The modeling of dependent light scattering effects in dense media strongly depends on the value of the relative index of refraction of the system: (1) For low nr, the use of single coherent scattering approximation can lead to a fairly accurate modeling provided the particles' shape can be approximated by spheres and that their spatial correlation is mainly driven by a hard sphere potential.
Nonetheless, this paper largely addresses negative index of refraction, as it serves as an observable milestone and a proof of concept in science's ability to steer and otherwise manipulate light, which is essential for achieving a cloaking capability.
The index of refraction is a fundamental property of a substance, and its determination may provide valuable diagnostic information about minerals and crystals.
All known materials have index of refraction which is more than one however in 1968 Veselago [1] found that it is possible to make a material that has index of refraction less than one, even negative.
Future applications in optical circuit elements and the boosting output power of LEDs are described, and the chapter on the optical properties of ZnO discusses methods for measuring the index of refraction, among other issues.

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