Photonics Dictionary

A circular optical wedge (prism of small refracting angle) mounted to be rotated in the path of light rays to divert the line of sight to a restricted degree.

Ability of a laser to resist variations in output power caused when it is slowly rotated about its optical or symmetrical axis.

One of the types of change in the energy levels of molecules or atoms in a laser that can result in lasing action. Because the energy levels between rotational states are small, such lasing action is...

A roughening laser is a laser-based surface modification technique aimed at altering the surface texture of a material to achieve specific properties such as enhanced adhesion, light diffusion, or...

A term used to describe a very coarse grinding process.

The circle that contains the slit, grating and primary astigmatic focus of a concave diffraction grating.

The mounting of a concave diffraction grating and a plate holder at the ends of a rigid bar. The ends follow separate straight tracks that intersect perpendicular to each other. The slit is located...

RTSP, or real-time streaming protocol, is a network control protocol designed for controlling streaming media servers. It is used for establishing and controlling media sessions between endpoints....

The optically pumped, solid-state laser that uses sapphire as the host lattice and chromium as the active ion. The emission takes place in the red portion of the spectrum.

A digital imaging method whereby the first gray level in the ordered sequence and the position of the first lengths of all runs are specified; used when there are only two possible gray levels...

A digital imaging method whereby the first gray level of each sequential point-by-point sample and its position in the succession of gray levels is encoded. It is used when there is a tendency for...

A term describing a type of scratch.

A ruticon is an opto-electronic device in which light going through it can be modulated by an electric field. The intensity distribution of the resulting image can be precisely controlled....

The term "Rydberg atom" refers to an atom in a highly excited state where one or more of its electrons are in a Rydberg orbital. A Rydberg atom is characterized by having an electron orbit that is...

The movement of the eye as it focuses on details of a scene. Some imaging systems mimic this movement by small, rapid scanning motions of the sensor.

A term used to describe a saddle-shaped -- i.e., convex along one axis, concave along the other -- polished surface, generally an error, whose contours are apparent by the shape of Newton's rings.

Filtered light to which photographic or other photosensitive materials are not responsive; used to illuminate darkrooms when film is being processed. The color of the filter varies according to the...

1. In the geometric sense, an abbreviation for the term "sagitta,'' the height of a curve measured from the chord. and it is exact for a parabola. 2. Conforming a sheet of glass to a...

The shape of the edge of a concave surface when the depth of the bevel plane to the vertex of the surface is controlled to a required distance.

Formula that describes the thermal equilibrium of gas electrons and ions as a direct function of variations in temperature.

On a chromaticity diagram, the point that denotes the chromaticity sample.

A device that acquires a signal and then stores it for a specified period of time before processing, and used, for example, to reduce noise as in correlated double sampling.

A crude area on the polished surface, produced during coarse grinding, that subsequent fine grinding does not remove, owing, to some extent, to coarse grains of grinding sand that mixed with finer...

The simultaneous exposure of two holographic plates with emulsions facing the object. After deformation, a second pair of plates is exposed to the deformed object. The back plate of the initial pair...

Sapphire crystal refers to a transparent, single-crystal form of aluminum oxide (Al2O3) known as corundum. It is one of the hardest known materials, second only to diamond on the Mohs scale of...

Sapphire optical fiber is a type of optical fiber made from single-crystal sapphire, which is a form of aluminum oxide (Al2O3) that is highly transparent in the infrared region of the electromagnetic...

A sapphire window refers to a transparent optical component made from sapphire crystal. Sapphire is a single-crystal form of aluminum oxide (Al2O3) that is highly prized for its exceptional optical...

Sapphire refers to a crystalline form of aluminum oxide (Al2O3) that is used in various optical and photonic applications due to its exceptional optical, mechanical, and thermal properties. Sapphire...

A direct-readout television pickup tube.

A saturable absorber is a type of optical device that exhibits variable absorption properties depending on the intensity of incident light. In essence, it becomes less absorbent as the light...

1. The decrease of the absorption (or gain) coefficient of a medium near some transition frequency when the power of the incident radiation near that frequency exceeds a certain value. As long as the...

1. A polariscope consisting of a Savart plate and a tourmaline plate analyzer, and used to produce parallel color fringes by transmitting polarized light. 2. A polariscope composed of an analyzing...