“refractive index”的概念、定义、翻译、参考文献-科学参考

refractive index

Physics

Symbol n. The absolute refractive index of a medium is the ratio of the speed of electromagnetic radiation in free space to the speed of the radiation in that medium. As the refractive index varies with wavelength, the wavelength should be specified. It is usually given for yellow light (sodium D-lines; wavelength 589.3 nm). The relative refractive index is the ratio of the speed of light in one medium to that in an adjacent medium.

The refractive index is given by the square root of the product of the relative permittivity (ε‎) of a medium and its relative permeability (μ‎); i.e. n=√(εμ‎). It is customary to take the positive square root. However, if both ε‎ and μ‎ are negative, as can happen in a metamaterial, it is necessary to take the negative square root; i.e. there is a negative refractive index.

See also refraction.

Astronomy

A measure of the refractive power of a transparent medium such as glass. Mathematically, the refractive index is the ratio of the sines of the angles of incidence and refraction as light passes into the medium. These angles are measured from the normal (a line at right angles to the edge of the medium). The angle of incidence, at which the light enters the medium, is greater than the angle of refraction, at which it travels through the medium. A typical refractive index for glass is about 1.5.

Geology and Earth Sciences

When light travels from air into a substance its velocity is reduced. The light path is also refracted into the substance, and the relationship between the angle of incidence (i) and the angle of refraction (r) is a constant (Snell’s law). This constant (n) is the refractive index of the mineral and is determined by: sin i/sin r = n. The refractive index is also the ratio of the velocity of light in air (V) to the velocity of light in the mineral (v): n = V/v.

单词	refractive index
释义	refractive index Physics Symbol n. The absolute refractive index of a medium is the ratio of the speed of electromagnetic radiation in free space to the speed of the radiation in that medium. As the refractive index varies with wavelength, the wavelength should be specified. It is usually given for yellow light (sodium D-lines; wavelength 589.3 nm). The relative refractive index is the ratio of the speed of light in one medium to that in an adjacent medium. The refractive index is given by the square root of the product of the relative permittivity (ε‎) of a medium and its relative permeability (μ‎); i.e. n=√(εμ‎). It is customary to take the positive square root. However, if both ε‎ and μ‎ are negative, as can happen in a metamaterial, it is necessary to take the negative square root; i.e. there is a negative refractive index. See also refraction. Astronomy A measure of the refractive power of a transparent medium such as glass. Mathematically, the refractive index is the ratio of the sines of the angles of incidence and refraction as light passes into the medium. These angles are measured from the normal (a line at right angles to the edge of the medium). The angle of incidence, at which the light enters the medium, is greater than the angle of refraction, at which it travels through the medium. A typical refractive index for glass is about 1.5. Geology and Earth Sciences When light travels from air into a substance its velocity is reduced. The light path is also refracted into the substance, and the relationship between the angle of incidence (i) and the angle of refraction (r) is a constant (Snell’s law). This constant (n) is the refractive index of the mineral and is determined by: sin i/sin r = n. The refractive index is also the ratio of the velocity of light in air (V) to the velocity of light in the mineral (v): n = V/v.
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