Photonics Dictionary: P

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

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...

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

A lens or mirror surface that is perfectly flat.

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

A five-sided prism containing two reflecting surfaces at 45° to each other, and two refracting faces perpendicular to the entering and emerging beams. The deviation angle of 90° is...

A surface that obeys Lambert's cosine law and has a reflectance of unity.

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...

In optics and photolithography, a phase mask refers to a device that modifies the phase of light waves passing through it. The phase mask is used to control the spatial distribution of the light's...

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 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...

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...

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...

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...

A spectroscopic process that detects and analyzes the discharge from an extrinsic surface with less than bandgap light. This method may determine the extrinsic surface-state energy levels of a...

The emission of an electron from a surface that occurs when a photon impinges upon the surface and is absorbed. This effect is the means by which photons may be detected.

The electron emission from a substance or instrument whose surface has been bombarded by a suitable amount of radiation.

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

A technique proposed for studying the atomic structure of crystals by measuring the interference pattern generated when the crystal is illuminated by a burst of finely tuned x-rays. The resulting...

Surface analysis by means of photon induced electron emission. PEM methods provide high lateral resolution of the observed sample.For surface material sciences PEM allows the investigation of...

Photogrammetry is a technique used to obtain accurate three-dimensional measurements of objects and environments through the analysis of photographs or imagery. It involves extracting information...

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 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,...

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

An instrument in which visible light beyond the critical angle from a metallurgical microscope is focused on a reference surface. A certain fraction of the incident light tunnels through air to the...

A surgical procedure for correcting vision by reshaping the outer surface of the cornea through the use of a laser system.

Photoresist is a light-sensitive material used in photolithography processes, particularly in the fabrication of semiconductor devices, integrated circuits, and microelectromechanical systems (MEMS)....

Noise created by patterns imaged on a CCD surface. Pixel sensitivity is altered by responsivity during illumination.

The recording achieved when a surface, illuminated by a signal-controlled light beam, emits electrons or reacts in some manner.

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

The apparent surface of the sun or a star from which light appears to radiate.

Photovoltaic (PV) refers to a technology that converts sunlight directly into electricity using semiconductors. The term "photovoltaic" is derived from the words "photo," meaning light, and...

A type of adsorption in which the adsorbed layer is attached to the adsorbent surface by an attractive force between the atoms or molecules rather than by a chemical bond (chemisorption).

A structure consisting of a thin film of liquid crystal sandwiched between light-polarizing filters that have received a surface lubricant. Depending on motion, the transducer acts as a highly...

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.

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

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

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.

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