The ratio of the speed of light in a vacuum to its velocity in a transmitting medium, such as an optical fiber core.
The ratio between the speed of light through air to the speed of light through another medium; the ratio determines how much a ray of light will bend as it passes through a given medium.
the ratio of the speed of light in a vacuum to its speed in some other medium. This will determine how much light rays are bent. When using immersion objectives it is important to keep the values as close together as possible.
The ratio of the velocity of light in a vacuum to the velocity of light in a refractive material. Short pass filter A filter which transmits the shorter wavelengths and rejects the longer wavelengths
The ratio of the speed of visible light in air to that in a substance. Each substance has a particular refractive index that is unique to that substance, so measurement of the refractive index is used to assist in the identification of a substance.
The numerical ratio of the speed of light in a vacuum to its speed in a substance.
The ratio of the velocity of light in two substances of different density.
The ratio of the velocity of light in a vacuum to its velocity in a material such as a fiber. Also, the ratio of the sine of the angle of incidence of light on the material to the angle of refraction to the light. Refractive index of any material varies with the wavelength of the light. Also called index of refraction. In a fiber, core refractive index must be greater than that of the cladding.
An index to define the amount of refraction a wave will undergo when it enters a medium.
Index of Refraction. The relative "density" of a transmissive material as a comparison of the speed of light in the material in question to the speed of light in free space.
(RI) The ability of the lens to bend light. Materials that bend the most light have the highest refractive index.
The ratio of the speed of light in a vacuum to its speed in a given material such as glass. The larger the ratio, the more the light entering the material is bent. Important in fiber optic technology.
A mathematical constant equal to the ratio of the velocity of light in a vacuum (which is approximately equal to the velocityof light in air) to that in a substance or mineral. The refractive index determines the angle at which light bends when it enters a substance at and oblique angle.
A technical term used to describe the effect of a lens in causing light rays to bend; important aspect in lens design.
A measurement of the degree to which a substance bends light waves.
Numerical value that describes the refraction of light when it passes through the boundary of two different materials.
Treated gems Veneer stone
(n) The ratio of the speed of light in a vacuum (c) to the speed of light in an alternate medium(v). n=c/v
The amount of refraction that takes place in a particular substance, which is a direct connection to the speed of light in that substance. The higher the refractive index, the greater the amount of dispersion, which increase the brilliance of a material. The refractive indices of gems are measured with a refractometer. Gems can be identified by measuring their refractive indices(plural)
1. a measure of the extent to which a transparent object may bend the incident light path; 2. the ratio of velocity of light in vacuum (or air) to its speed in another medium; symbol h = 1.33 for water, 1.413 for lens of eye.
The amount a beam of light bends as it enters a gemstone and then strikes a subsequent surface(s). The amount of refraction depends on the structure of the stone.
The ratio of the velocity of light in vacuum to that in an optically dense medium.
a number that represents how much light is slowed down as it passes through a substance
Measure of a materials ability to bend light.
A measurement of the bending of a beam of light when it passes from material into another and the two materials have different densities (e.g. light passing from air through water is bent because air and water have different densities).
Also R.I. A number assigned to a materialâ€(tm)s ability to bend light. Diamond, at 2.42, bends light a lot while quartz, at 1.55, is much lower on the scale and is much less brilliant.
the ratio of the speed of EM radiation in a medium divided by the speed of EM radiation in a vacuum, c. c=2.99 million km/s (2.99E8 m/s). The refractive index varies with wavelength according to dispersion. Glass has a refractive index (eta) of about 1.50 at 590 nm, while air is about 1.00 at 590 nm (almost the same as in vacuum).
Is a measure of how light is refracted. See Refraction above. Part of identifying a gemstone is to test the refraction.
The ratio of the velocity of light in air to the velocity of light in a given material. Symbolized by n.
Measures the slowing down and bending of light rays as they enter a gemstone. Maybe used to identify gem species.
A process using a refractometer to measure the speed and angle of light entering a gemstone. Very important for gem identification.
A process developed by Willebrord Snell that incorporates a refractometer to measure the speed and angle of light as it enters a gemstone. It is used in gem identification.
the ratio of the velocity of light in air to its velocity in the new substance is known as the refractive index of that substance. Almost every gem material has it's own unique specific refractive index (R.I.). Determination of the RI is probably the most conclusive measurement available to gemologists
It is the amount of refraction taking place in a particular substance which is directly co-related to the speed of light in that substance. The refractive index is directly related to the amount of dispersion that further increases the brilliance of a material. Refractive indices are measured with a refractometer.
The moisture, or conversely the soluble solids in honey, is determined by measuring the refractive index of honey using a refractometer. Because the refractive index of honey is different from that of a sucrose solution at the same concentration, a special moisture chart must be used. This chart is found in AOAC Method 969.38 (see Analytical Methods). Using the "Brix" or "Sucrose" scale will provide inaccurate values for honey.
Measure of the refracting power of a medium (e.g: 1.6 for water, 1.46 to 1.95 for optical glass, etc.).
the ratio of the speed of light in air to the speed of light in the specified material.
This number is a dimensionless quantity that is related to the ratio of the speed of light in air (or vacuum) to its speed in another medium.
the ratio of the velocity of light in a vacuum to the velocity of light in some medium.
In a wave-transmission medium, the ratio between the phase velocity in free space and in the medium.
A measure of the amount of refraction. Numerically equal to the ratio of wave velocity in a vacuum to a wave speed in the medium, i.e., n=c/v where: v is actual speed, and c is speed of light in a vacuum.
See index of refraction.
A property of optical materials that relates to the velocity of light in the material. Learn more about Refractive Index...
a measure of a clear substance’s ability to slow photons, and thereby bend the direction of travel of off-axis rays of light. The denser the material, the more it will slow photons, and therefore bend the direction of travel. Material Vacuum of space 1.00000 Air 1.00029 Distilled water 1.333 Seawater (Average) 1.341 Window Glass 1.49 Polycarbonate 1.586 Diamond 2.417
A mathematical description of the intrinsic properties of a material that govern its interaction with electromagnetic radiation; usually represented by a real part (n), the refractive index, and an imaginary part (), the absorption index.
The ratio of speed of light in a vacuum to that in a given medium, such as glass, water or oil.
3.66 Properties at temp=300 K,wavelength not given for refractive index Semiconductor Sensors,by S.M.Sze,UMC chair professor,John Wiley & Sons ,INC.Appendix D, p.535
Developed by Willebrord Snell in the seventeenth century. This process usually incorporates a refractometer, which measures the speed and angle of light as it enters a gemstone. The refractive index is often the key to gem identification.
Ratio of the speed of light in a vacuum to the speed of light in a material.
The extent to which a lens focuses incoming light. back
The ratio of the velocity of light in a vacuum to the velocity of light in a specific material. Using 1.0 as the base reference, the higher the number, the slower the speed of the lightwaves in the material.
A measure of the degree through which light is refracted when passing through a particular material compared to a vacuum.
The ratio of the velocity of light in a vacuum to the velocity in the substance. The velocity in the substance is dependent on the composition, concentration and temperature of the substance. When the composition and temperature are known the refractive index becomes a measure of concentration and is widely used as a rapid, convenient measure of concentration for glucose syrups and, in the paper industry, for starch pastes.
This is a constant when links the angle at which a ray of light will be before and after refraction. A refractive index is from one material to another
This is the ratio of the velocity of light in a certain medium compared with its velocity in air.
The measurement of how much a light ray is bent and reflected as it enters or leaves a gemstone. Generally, the higher the R.I. the greater the brilliancy of the stone.
A measure of the angle of the deflection of light as it passes from one substance to another.
The relationship of the speed of light through a vacuum and the speed through another substance.
(index of refraction) The ratio of the velocity of light in a vacuum to the velocity of light with in a material.
A ratio between the velocity of light in air and that of light through a particular substance. The index of air is 1.00 and all indices are referred to the index of air, i.e., the index of water being 1.33 means that the speed of light in air is 1.33 times greater as the speed of light in water.
A property of optical materials that relates to the speed of light in the material versus the speed of light in a vacuum.
The ratio of the velocity of light in a vacuum to its velocity in the medium. Synonym: Index of Refraction.
numerical value indicating the light bending power of a medium such as glass. The greater the bending power, the greater the refractive index.
Ratio of light velocity in a vacuum to its velocity in the transmitting medium.
Deflection of light from a straight path as a function of change in velocity caused by the difference in densities of two mediums as the light passes between them. It can be used as a chemical detection system following HPLC.
A measure of the extent to which an oil or liquid fat will bend a beam of light when passing through from air; it is measured by a refractometer.
The refractive index is a measure of how light is refracted in a substance (like a gemstone). In doubly-refractive stones, the light is split into two light rays when it enters the stone, and the rays travel in different paths - so these stones have more than one refractive index.
The ratio of the velocity of light in a vacuum to that in a given material. It may be used in fibre identification or as a measure of fibre orientation. (See also birefringence.)
The refractive index (or index of refraction) of a medium is the inverse ratio of the phase velocity of a wave phenomenon such as light or sound and the phase velocity in a reference medium. It is most commonly used in the context of light with vacuum as a reference medium, although historically other reference media (e.g. air at a standardized pressure and temperature) have been common. It is usually given the symbol n.