Photonics Dictionary: P

Piezoelectricity is a property exhibited by certain materials in which they generate an electric charge in response to mechanical stress or deformation, and conversely, undergo mechanical deformation...

Piezoresistance is a phenomenon in materials science and physics where the electrical resistance of a material changes in response to applied mechanical stress or strain. This change in resistance...

A short length of optical fiber permanently fixed to a component and used to couple power between it and the transmission fiber.

A PIN photodiode is a type of photodetector or semiconductor device used to convert light signals into electrical signals. The name "PIN" is derived from the arrangement of the three semiconductor...

An aberration of a lens system caused by an increase in lens focal length as the field angle increases. The amount of distortion normally increases as the cube of the image height.

A lensless photographic camera that uses a small sharp-edged hole as its aperture. The light passed by this aperture onto the camera's film plane produces a soft-edged image that has a wide field of...

A type of eyepiece, or the modification of an eyepiece, in which a small hole, without a lens, functions as the eye lens; used in the adjustment and alignment of microscopes.

In image processing and elsewhere, generally an adjective to describe an assembly-line arrangement for performing a task. For example, an image is put through one kind of processing step and then...

A vacuum gauge designed to measure very high degrees of vacuum by thermal conduction.

Motion of a fiber into and out of the ferrule. This effect is often caused by changes in temperature.

The micrometer-size depressions that store data digitally in an optical data storage medium.

Pitch for polishing mixed with other materials to give it the right viscosity so that it will follow the fine-ground lens surface and yet maintain contact at all times.

In positioning, rotation about an axis normal to the line of sight. Also known as attitude.

Pixel binning, also known as pixel merging or pixel combining, is a technique used in digital imaging and camera technology. It involves the combining or grouping of adjacent pixels on an image...

In digital image processing, a subcategory of frame processing that treats each pixel in terms of its relationship to adjacent pixels. Perceived brightness trends facilitate spatial filtering.

Pixel pitch refers to the distance between the centers of two adjacent pixels on a display screen or imaging sensor. It is typically measured in millimeters and is a crucial specification in...

A pixel, short for "picture element," is the smallest controllable element of a digital image or display. It is a fundamental unit that represents a single point in a raster image, which is a grid of...

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 device used in the sputtering of thin films, in which a magnet system on the back of the cathode deflects the electrons, lengthening the ionization path. The accelerated ions transfer their...

The formula describing the spectral radiant emittance of a perfect blackbody as a function of its temperature and the wavelength of the emitted radiation. where Wλ equals radiation...

The universal constant h that has a value of 6.6260693 x 10-34 Js. A quantum of energy is equal to the product of the frequency of the radiation and Planck's constant.

A fundamental law of quantum theory which states that the discrete quanta of energy transfers associated with electromagnetic radiation are proportional to the frequency of the radiation.

Locus of points on a chromaticity diagram that includes the chromaticities of blackbody radiators.

A synonym for blackbody or complete radiator.

A surface that has no curvature; a surface that is perfectly flat.

An instrument designed to give precise and rapid detection of changes in tumor growth as well as the location of small tumors by providing a three-dimensional picture of the tissue.

A transmission or reflecting grating with a flat or plane surface requiring a lens or concave mirror to focus the spectrum.

A two-dimensional hologram.

The generation of a grating on a flat surface by means of a series of interference fringes formed by a holographic process. See holographic grating.

An imaginary plane dividing a body into two parts so that each part is the precise mirror image of the other in the plane of symmetry.

A wave whose surfaces of constant phase are infinite parallel planes normal to the direction of propagation.

A light beam whose electric vectors all vibrate in a single fixed plane.

A camera system used for microphotography in which the document to be recorded is on a flat bed, perpendicular to the lens axis. The camera head is located above the copyboard on a column and may be...

A manufacturing process used to construct substrates for large optical components. Used with IR materials, planform bonding permits the joining of several smaller pieces to be used in place of a...

A lens or mirror surface that is perfectly flat.

A lens with one plane surface and one concave surface.