Photonics Dictionary: P

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 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.

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 paraboloidal surface on which the image is located when there is no astigmatism.

Periodic interruptions of a light beam incident on an absorbing medium that produce heat, expansion and acoustic wave generation. Since the amplitude of this wave is proportional to the absorbed...

Generation of an acoustical signal by a sample exposed to modulated light.

A device for measuring absorption coefficients in which a confined, nonabsorbing gas fills the space inside the cell between the two windows, which are made from a weakly absorbing medium.

Abbreviated PAI. An imaging modality with a hybrid technique based on the acoustic detection of optical absorption from endogenous chromophores or exogenous contrast agents. Light is absorbed by the...

A method for obtaining the optical absorption spectra of solids, semisolids, liquids and gases. PAS is inherently insensitive to reflection or scattering from the sample, analyzes opaque samples and...

Photobleaching is a phenomenon in which the fluorescence of a fluorophore (a fluorescent molecule or dye) is permanently reduced or eliminated upon prolonged exposure to light. This process occurs...

Material used to integrate photoconductors into electro-optical systems. It should provide low resistance to the flow of charge, avoid recombination of the charge carriers, inject only majority...

Photodynamic inactivation (PDI) is a therapeutic approach that utilizes the combination of light, a photosensitizer, and molecular oxygen to induce cell death or inactivate microorganisms. This...

A photonic crystal surface-emitting laser (PCSEL) refers to a type of laser diode that emits light from its surface rather than from the edges. Photonic crystals are periodic nanostructures that...

Photonics contract manufacturing refers to the outsourcing of the production of photonics-related components, devices, or systems to specialized manufacturing firms. Photonics involves the...

Participates in a reaction only in the presence of light and radiant energy. Besides 3D printing, photoreactive agents also have an application in light therapy. By absorbing light, photoreactive...

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 surface from which electrons are ejected by the incidence and absorption of photons.

Photosynthetically active radiation (PAR) is the 400- to 700-nm region (visible light) of the electromagnetic spectrum that is absorbed and used by the plant for photosynthesis. Also referred to as...

A tachometer consisting of a light source, rotating perforated wheel and phototransistor to measure the rates of rotation of components. The phototransistor counts the flashes formed when the wheel,...

Low-insertion-loss fiber coupler fabricated from a sheet of light-sensitive material laminated onto a fused quartz substrate and exposed through a suitable mask. After development of the plastic...

A lens or mirror surface that is perfectly flat.

A plasma accelerator is a type of particle accelerator that uses electric fields and magnetic fields to accelerate charged particles, typically electrons or ions, by exploiting the motion of charged...

The direct cladding used for fused silica cores to create large numerical aperture fibers and used as overcoats to glass-clad fibers to reduce microbend loss and increase mechanical protection.

A crystal diode whose rectifying activity is determined by the touching of the crystal to a finely pointed wire surrounded by a material of opposite type.

A crystal-based device that combines and adjusts the intensities of multiple wavelengths of laser light in order to obtain the desired output wavelength.

The polymerase chain reaction (PCR) is a widely used molecular biology technique used to amplify a specific segment of DNA (deoxyribonucleic acid) through a series of temperature-controlled cycles....

Factor that relates the pulse spread occurring in a graded-index fiber to that of an equivalent step-index fiber having an identical refractive index difference between core and cladding (that is, an...

A phage, short for bacteriophage, is a type of virus that infects and replicates within bacteria. Phages are composed of genetic material (either DNA or RNA) surrounded by a protein coat. They are...

A polygonal mirror, also known as a multifaceted mirror or facet mirror, is a type of optical component used in various laser systems, optical scanners, and imaging devices. It consists of a flat or...

A semiconductor material in which the dopants create holes as the majority charge carrier. It is formed by doping with acceptor atoms.

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...

Black and white film that has a wavelength sensitivity similar to that of the eye.

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 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 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...