Photonics Dictionary: P

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

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.

A pair of waveguides with axes normal to the plane and that guide uniform cylindrical waves.

A device that converts data transmitted in the parallel mode to a sequence of bits at a single frequency for output in the serial mode.

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

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 term perovskite refers to a specific crystal structure commonly found in various materials. Perovskite structures have a cubic arrangement of oxygen ions, forming a framework within which other...

A phase-modulated sensor is a type of sensor that uses modulation of the phase of a signal to measure changes in a physical quantity. In such sensors, variations in the phase of the signal are...

A type of matched filter that responds only to the phase of incoming light; the output has a much greater intensity than that of a classical matched filter, which responds to phase and amplitude. The...

A type of glass that includes phosphorus pentoxide and that, unlike silica-based glass, is resistant to hydrofluoric acid.

The property of a phosphor that determines its ability to emit light for a time after the stimulus has been extinguished. Persistence may extend to over a minute.

An instrument used to detect and measure radiant energy by the formation of a chemical reaction.

The discrepancy between the absolute luminance threshold and the photochromatic threshold.

A photographic recording instrument that measures deviation from the vertical of a drilled well or mine.

Photoconductive antenna (PCA) is a semiconductor element that generates or detects high-frequency electromagnetic signals. Compact PCAs based on gallium arsenide (GaAs) or indium gallium arsenide...

A device for detecting visual and infrared radiation using a photoconductor as the principle sensing element.

A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical signal. Photodetectors are widely used in various applications, ranging from...

A photodiode detector is a semiconductor device that converts light into an electrical current. It operates based on the principle of the photoelectric effect, where photons of light incident on the...

A system having a photoelectric detector for the measurement of three quantities related by linear combination to tristimulus values of a sample.

A device used to count objects that pass a given point by allowing each object to obstruct a beam of light falling on a photocell. Slow counting rates can be recorded by a mechanical counter, but...

A device consisting of a microammeter, a photovoltaic cell and a battery. It is used for the measurement of scene brightness and the determination of correct exposure for photographic processes.

A filter fluorometer that uses a photomultiplier tube to detect the fluorescence of a sample.

Also known as electronic photometer. A photometer with a photocell, phototransistor or phototube for measuring the intensity of light.

An instrument used to measure the temperature of a source through the use of photoelectric cells to detect and measure the intensity of the light emitted by the source.

A photoelectric photometer used to measure the reflectance of a surface.

A system that consists of a spectrophotometer with a photoelectric detector for measurement of radiant energy.

An electronic tube instrument in which the anode current varies with the intensity of light incident on the cathode.

A photometer that uses a photoemissive tube to detect and measure light. See photoelectric photometry.

A measure of the total light passed by a shutter during an exposure, compared with the light that could be passed by an idealized, infinitely fast shutter fully open for the same extreme time.

A device used to compare the luminous intensities of two sources by comparing the illuminance they produce.

A type of laser spectroscopy used to measure short-lived isotopes by observing sudden bursts of fluorescence resulting from repetitive excitation of an atom or molecule.

A device used to evaluate the luminance of a surface by determining the number of photons emitted from a sample surface area.

An infrared detector in which radiation passes through a doped germanium crystal, creating a voltage drop that can be measured in terms of incident intensity.

A type of computer in which the electronic circuits, which process data serially, are replaced by photonic circuits capable of parallel processing and thus of much greater speed and power. Where the...

A photonic integrated circuit (PIC) is a compact and integrated device that incorporates multiple photonic components and functions on a single chip, similar to the way electronic integrated circuits...

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.

A small section of the surface of a sensor corresponding to a single pixel in the image.

A document-transmitting process that uses a cylinder that rotates the document to be scanned and detected by a photoelectric cell. The cell transforms the light into electrical energy that may be...

A camera equipped with angular scales in altitude and azimuth. The scale readings are imprinted on the film when an exposure is made. The exact point indicated by the scale readings is shown by...

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,...

An interferometric technique for the generation of precision gratings that allows for sequential exposure of small segments in the writing of a large grating, allowing increased intensity that...

Piezoelectric motion systems are mechanical systems that utilize piezoelectric materials to generate controlled motion or displacement. Piezoelectric materials exhibit the piezoelectric effect, which...

Piezoelectric transducers are devices that utilize the piezoelectric effect to convert electrical energy into mechanical vibrations or vice versa. The piezoelectric effect is a property exhibited by...

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.