Photonics Dictionary: P

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

The arrangement of two Porro prisms so that the inverted image formed by certain types of optical instruments is the same as the object. The first prism, which is set at 90° to the second, inverts...

An assembly of prototype instruments, equipment and/or software designed to perform all the functions of a concept or idea which, when operated as a system, produce evidence, results or data...

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 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...

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...

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

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 Peltier cooler, also known as a thermoelectric cooler (TEC) or thermoelectric module, is a solid-state device that uses the Peltier effect to transfer heat between two electrical junctions. It can...

A theoretical, ideal lens capable of producing perfect images. Used as a lens design and analysis tool to image collimated output from an afocal system.

Near the boundary or edge of the field of an optical system; the outer fringe.

An optical instrument designed to displace the line of sight in a vertical direction. For submarines and other military uses the periscope is a long tube containing prisms at both ends and...

In the SI system, prefix meaning 1015.

An optical system used to examine the pharynx.

Phase distortion refers to a change in the phase relationships between different frequency components of a signal. In the context of signal processing, it occurs when the phase response of a system...

Phase matching is a crucial concept in the field of optics, particularly in nonlinear optics and the generation of coherent light. It refers to the condition where the phases of two or more waves,...

A phase screen, in the context of optics and wave optics, refers to a surface or medium that introduces a phase delay to an incident wavefront passing through it. This concept is often used in the...

An erasable data recording and storage medium that uses a laser to heat the crystalline surface of the disc to a certain temperature, at which it becomes amorphous and records a bit of information;...

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 method of coding information in a communications system where the shift in the phase of an electromagnetic wave represents a particular bit or character.

A phonon is a quantum of vibrational energy associated with the periodic motion of atoms or molecules in a crystalline lattice. In simpler terms, phonons are quanta of lattice vibrations in a solid...

A method for remote measurement of the temperature of moving surfaces in harsh environments by using a laser to stimulate fluorescence of thermographic phosphors and then measuring the decay times by...

A process used in pyrometry and photothermometry to create a photographic record of a surface's temperature gradients. Essentially, it involves the exposure of a glowing phosphorescent surface to the...

Photocathodes are specialized materials or surfaces that exhibit the photoelectric effect, wherein the absorption of photons leads to the emission of electrons. When photons with sufficient energy...

The term photochemical pertains to chemical processes or reactions that are initiated or influenced by the absorption of light. Photochemical reactions involve the interaction of light, often in the...

A method of producing disks for erasable optical data storage. Information is recorded by a laser beam that generates pits on the surface of the disk while it is being cryogenically cooled. Erasure...

Photochromic refers to a property exhibited by certain materials, typically organic compounds or dyes, which undergo reversible changes in color when exposed to light. Specifically, photochromic...

An optical medical instrument that uses an intense, precisely focused beam of light to stop weakened blood vessels from hemorrhaging. The thermal effect of the beam strengthens the weakened vessels...

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...

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...

The process of determining, with the aid of plane-polarized light, the stress distribution in materials under complex systems of loading.

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

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 system mounted a few inches above a moving plane that consists of a light source, lenses and one or more phototubes. In this position, the scanner actuates the control equipment when the quantity...

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

A measure of the ability of a photographic system to record fine detail. Usually stated in terms of cycles per millimeter on the processed film.

A system in which the electrical signal embedded within an audio input signal is converted to a modulated light pattern and recorded on film.

Photoimmunotherapy (PIT) is a medical treatment approach that combines elements of phototherapy and immunotherapy to target and treat specific cells or tissues in the body. The key components of this...

Photolithography is a key process in the manufacturing of semiconductor devices, integrated circuits, and microelectromechanical systems (MEMS). It is a photomechanical process used to transfer...

A photomask, also known simply as a mask or reticle, is a key component in the photolithography process used in semiconductor manufacturing and other areas of microfabrication. It is a high-precision...

Photometry is the branch of science that deals with the measurement of light, particularly in terms of its intensity and the way the human eye perceives it. It involves the quantification of visible...

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...