Definitions

A light ray that has had its direction altered because of its traversing an air-to-glass interface at some angle. In an optical waveguide, a ray that is refracted from the core into the cladding.

The technique for measuring the index profile of an optical fiber by scanning the entrance face with the vertex of a high numerical aperture cone and measuring the change in power of refracted...

A wave of radiation that has undergone refraction.

A prism that often is used as a dispersing element in spectrographs and monochromators.

A transparent sphere that has an index of refraction that is different from that of the medium surrounding it; used in optics to demonstrate refraction and astigmatic image formation.

The bending of oblique incident rays as they pass from a medium having one refractive index into a medium with a different refractive index.

A measure of the relative difference in refractive index between two optical materials. Most commonly used in fiber optics where the refractive index contrast, D, is given as follows: where n1 equals...

A closely spaced series of well-known chemicals having a refractive index lying between 1.33 for water and 1.95 for a solution of phosphorus in carbon disulfide. They are used to identify powdered...

The description of the refractive index along a fiber diameter.

The mean square difference in refractive index for two separate points in space.

An instrument used to measure the refractive index of solids and liquids. Several types exist, the most common being the Abbe refractometer.

The method used to determine the refractive index of a given substance.

An Abbe refractometer is a scientific instrument used to measure the refractive index of liquids and solids. Named after the German physicist Ernst Abbe, this device operates on the principle of...

The ratio of the speed of light in a vacuum divided by the speed of light in the medium.

The acousto-photorefractive effect refers to a phenomenon in which acoustic waves (sound waves) interact with light waves (photons) within a photorefractive material, resulting in changes in the...

The angle formed between a refracted ray and the normal to the surface. This angle lies in a common plane with the angle of incidence. See also Snell's law of refraction.

Formulaic compensation to correct laser ranging data for the effects of horizontal refractivity gradients; it requires the horizontal pressure and temperature gradient at laser sites, which are...

The dispersion of a light ray striking the surface of a biaxial crystal, in which the resulting rays are reflected in a conical manner.

The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such as calcite, is placed between the eye and a pinhole in a card, two bright...

A transparent crystalline substance that is anisotropic relative to the velocity of light.

An alteration in the direction of the magnetic induction at the interface between two media of different permeability.

A type of refractometer designed to measure the refractive indices of liquids. A section of the instrument is immersed into the sample being measured.

The ratio of the velocity of light in a vacuum to the velocity of light in a refractive material for a given wavelength.

An instrument designed to measure the index of refraction of a gas by the interference patterns formed by two beams, one of which passes through a vacuum tube in which the gas is slowly released.

An artificial material, engineered to have a negative refractive index value, such that light or any other form of electromagnetic radiation bends in the opposite direction than it would in ordinary...

A surgical procedure for correcting vision by reshaping the outer surface of the cornea through the use of a laser system.

A material in which the refractive index varies according to changes in the light to which it is exposed. Lithium niobate is one example.

The quantity equal to the refractive index of one medium divided by that of a second medium.

The incident ray, the normal to the refracting surface at the point of incidence of the ray at the surface, and the refracted ray all lie in a single plane. The ratio of the sine of the angle between...

The refraction that would take place in an idealized atmosphere where the refractive index is reduced uniformly with height at the rate of 39 x 10-6 per kilometer.

A refractometer that has a greater resolving power than a standard refractometer, and that uses a pentagonal prism to split the light from a single slit into two beams.

A dispersion relation defined in order to value the reciprocal amount of dispersion. It is defined as the refractivity over the difference in index values of the shortest and longest visible...

The Abbe sine condition is a fundamental principle in optical physics that relates to the performance of an optical system, particularly its ability to produce high-quality images free from spherical...

The absorption index represents the imaginary component of the complex index of refraction, and not the real component. The imaginary component may characterize the attenuation per unit length...

An absorption lens is a type of optical lens that not only focuses or diverges light but also significantly absorbs certain wavelengths of the incident light. This dual function makes it different...

An achromatic prism is a type of prism designed to separate white light into its component colors (spectrum) without causing chromatic aberration. Unlike regular prisms, which disperse light but also...

Achromatism refers to the optical property of a lens, prism, or optical system that minimizes or eliminates chromatic aberration. Chromatic aberration is the phenomenon where different wavelengths...

Acousto-optic deflection refers to a phenomenon where the trajectory of light is altered by acoustic waves propagating through a material. This effect is utilized in acousto-optic devices, which are...

The angular change of an incident beam due to vibrational induced refractive index changes within a crystal.

An acousto-optic deflector (AOD) is a type of device that utilizes the acousto-optic effect to control the direction of light beams. It operates by modulating the refractive index of an optically...

Acousto-optic diffraction refers to the process where light passing through an optically transparent material is diffracted due to the modulation of its refractive index by an acoustic wave...

Acousto-optic modulation refers to the process of using acoustic waves to modulate the properties of light passing through an optically transparent material. This modulation occurs due to the...

An acousto-optic modulator (AOM) is a device that utilizes the acousto-optic effect to modulate the amplitude, phase, frequency, or polarization of a laser beam or other coherent light source. It...