Photonics Dictionary: P

In a semiconductor, the state created by the addition of a dopant that creates excess holes.

The finite amount of electrical charge generated in response to incident radiation and transferred from one storage element to the next in a charge-coupled device. Each packet corresponds to a pixel...

The transmission of data in groups (packets) of information~comma~ each handled as an aggregate.

1. In a photonic interconnect, the number of detectors in a given area. Detectors spaced too closely may give rise to crosstalk. 2. In the cross section of a fiber optic bundle, the ratio of fiber...

The ratio of the active core area of a fiber bundle to the total area at its light-emitting or receiving end.

The production of a positron-electron pair by a photon having energy greater than one mega-electron-volt, whereby some of the photon energy is converted to the rest mass of the pair.

In interlaced television scanning, an effect in which the lines of one field fail to fall exactly within the lines of the following field, both fields comprising one frame of the picture. The lines...

A camera designed to form a continuous record of an expansive section of the horizon. The typical panoramic camera is mounted to rotate about a vertical axis. A slit opening in the film plane and the...

The image distortion produced by a panoramic camera with a swinging lens or a swinging mirror in front of a fixed lens. The magnification is greatest in the center and diminishes to each side in the...

A lens system that is capable of producing a 360° image, or one that is very close to that. In recording, the image may be formed on a curved strip of film surrounding the lens, resulting in a...

A telescope so manufactured that the image remains erect and the position of the eyepiece is unchanged as the line of sight is pointed in any horizontal direction.

The condition in which the index of refraction in an optical fiber varies as a parabolic function of the radius.

A condenser composed of a paraboloidal reflector and used for dark-field illumination.

A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a paraboloidal surface through which the axis does not pass, and is known as an...

A saturated compound of carbon and hydrogen used as a liquid coating material for optical components in high-power laser applications. See liquid coating.

The angular difference in the direction of an object as seen from two points of observation. The angle subtended at the object by the base length of a rangefinder.

The optical phenomenon that causes relative motion between two objects when the eyepoint is moved laterally. When parallax appears in a telescope between the image and reticle, this indicates the...

Parallel scanning refers to a method of acquiring data or images simultaneously from multiple sources or in parallel, rather than sequentially scanning each source one after another. This approach is...

A mode of data transmission whereby bits of information are carried simultaneously at different frequencies over a single channel.

In a camera or cathode-ray tube, distortion that is designated by a lateral skewing of the reproduced image.

Means of amplifying optical waves whereby an intense coherent pump wave is made to interact with a nonlinear optical crystal to produce amplification at two other optical wavelengths. See parametric...

Oscillation in rod and disc amplifiers that critically limits the achievable energy storage.

A ray that behaves according to paraxial equations; one that lies close to and almost parallel to the optical axis.

Description of an optical system in which all the elements are aligned on the same axis.

In data transmission, a self-checking code using a separate bit (the parity bit) to assure that all bytes of transmitted data contain either an odd or an even number of bits. Upon receipt, the data...

Totally coherent radiation is produced by a purely monochromatic point source. In the real world the energy will have a limited bandwidth and the point source will subtend some angle resulting in...

Particle acceleration refers to the process by which charged particles, such as electrons or protons, gain kinetic energy and increase their velocity. This acceleration can occur in various natural...

A whole-flow-field technique providing instantaneous velocity vector measurements in a cross-section of a flow that is seeded with micron-sized particles. CCD or CMOS cameras and laser light sheets...

An array of lines in the infrared region of the emission spectrum of atomic hydrogen. Their wave numbers are expressed by the equation: where represents the wave number in the reciprocal centimeters,...

A mounting used for large concave gratings, whereby the slit, grating and plate holder lie in the Rowland circle, and the photographic plates lie along a large portion of the circle. In this way, a...

The criterion maintaining that if light follows a specific path through an optical system, it will, if reversed, traverse that same path in the opposite direction.

A pathogen is a biological agent, such as a virus, bacterium, fungus, protozoan, or parasite, that causes disease in its host organism. Pathogens have the capability to invade host tissues,...

A thin film or coating that forms on various finished surfaces. On optical surfaces it usually denotes aging.

A device that determines the lens shape in the cutting or edging phase of fabrication. It also is used to denote the arrangement of markings on a reticle.

The number of electrons that can share a principal quantum number by preventing identity between any two electrons' four quantum numbers, thereby permitting the periodic arrangement of the elements.