Photonics Dictionary

A vapor-phase oxidation process for fabricating graded-index optical fibers. It differs from outside vapor phase deposition in that the preform is developed radially rather than longitudinally. An...

Azimuthal polarization refers to a specific polarization state of light where the electric field vector of the electromagnetic wave points along the azimuthal direction (around the propagation axis)....

The rule stating that positive uniaxial crystals have greater absorption with respect to the extraordinary component of light, whereas negative crystals have greater absorption for the ordinary...

The ability of a camera to compensate in cases where a subject with a large amount of background light would otherwise be obscured by blooming or silhouetting.

A filter that suppresses a given range of frequencies, transmitting only those above and below that band. Also called bandstop filter.

In fiber optics, the limitation on performance imposed by the system bandwidth rather than the amplitude of the signal.

The negative distortion that causes a square grid pattern to be imaged as barrel-shaped.

An electron-beam tube in which the current to an output electrode is regulated by the transverse motion of the tube's electron beam.

In computer graphics, the point on the display screen where the electron beam is located before the display instruction is executed. On directed beam display points, vectors and other graphic...

A device (e.g., prisms, lenses, tubes) used to align a beam in a system.

Two formulas used in diffractometer analysis, the first giving the individual diffraction patterns of each aperture, the second representing the constant of the degree of an incoherent circular...

The high-speed electrons and positrons emitted by radioactive materials.

Unified notation for specification of reflectance in terms of both incident- and reflected-beam geometry; i.e., the ratio of reflected radiance in direction toward the viewer to the irradiance in...

It is often necessary to estimate the value of what a pixel would be between neighboring pixels. This is accomplished by interpolating (or inserting) the value of a pixel between neighboring pixels....

The adjustment of a binocular instrument so that the lines of sight of both telescopes are parallel.

The ability of the two eyes to see an object from two slightly different points of view. This difference allows an individual to perceive the depth and dimension of the object in view.

The application of observed operational processes of sophisticated living organisms to mechanical and electrical systems in order to analogize capabilities or efficiency.

The action of a biological system responding to a single or multiple coherent particles of light produced from a laser source. Examples of laser biostimulation include: retinal interaction of light...

The law given by the formula: that is, the frequency of radiation emitted or absorbed by a system when E2 and E1 are the energies of the states among which transition takes place, and h is...

In optical character recognition, an intermediate step between character location and feature extraction.

The illumination generally used in microscopy, whereby the specimen appears dark against a light background.

The degree to which a pixel in a digital image represents the analog brightness of the corresponding point in the original image. It is dependent largely on the number of bits devoted to representing...

Radiation that occurs perpendicular to the plane of the radiation device.

The behavior of microscopic solid particles suspended in a fluid, first observed by botanist Robert Brown in 1827 as a continuous random motion.

Any known value derived from standard analysis that serves as a reference to the accuracy of an instrument or process in determining one or more variables.

The use of the photographic process to produce precision copies of an original image that are many times smaller in size. One of its many applications is in microcircuitry.

Carbonization is a process in which organic materials are heated in the absence of air, leading to the decomposition of the material and the production of carbon-rich residue. During carbonization,...

Carrier injection refers to the process of introducing charge carriers (either electrons or holes) into a semiconductor material. Semiconductors are materials with electrical conductivity between...

In a series of amplifiers, amplification by each of the preceding output.

The amplitude modulation through the application of modulating voltage to the cathode circuit.

A plane that lies at right angles to the tube axis that has the deflection center.

An ion carrying a positive charge and thus attracted to the cathode during electrolysis.

In a reflecting telescope, the obstruction of the primary mirror by a secondary mirror which blocks a small amount of the light reflected by the primary mirror and introduces additional diffraction.

In a perfectly centered lens, the mechanical axis (defined by the ground outside the diameter of the lens) is made to be exactly coincident with the optical axis (defined by a line through the...

The radiation produced when a charged particle traverses a medium that has a refractive index considerably greater than unity. The moving particle has a velocity that exceeds the velocity of light in...

The breakdown of the bonds in polymer chains caused by illumination.

A cathode-ray tube that generates symbols for use in other displays. The tube operates by scanning specific characters on the target and generating them as video signals to other cathode-ray systems.

A charge-injection device (CID) refers to a class of devices that manipulate and detect electrical charge within a semiconductor material. Charge-coupled devices are a specific implementation of this...

Chemical vapor deposition (CVD) equipment refers to a class of specialized apparatus used in the process of chemical vapor deposition, a technique for depositing thin films of various materials onto...

Chemical vapor deposition is a process of applying dopants to a glass bait by flame reactions of gaseous compounds. See also outside vapor-phase oxidation; inside vapor-phase oxidation.

The binding of gas to a surface or in matter by chemical activity.

A laser whose pulses are expanded, using gratings and optical fibers, before amplification and compressed to increase beam intensity without damage to the optical train.

Chirped pulse amplification (CPA) is a technique used in laser physics to amplify ultrashort laser pulses to high energies without causing damage to the amplifying medium. The method was first...

Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a lens or optical system, leading to a failure to focus all colors to the same...

Change of sensitivity of the eye leading to changed color perception.