Photonics Dictionary: P

The point spread function (PSF) is a fundamental concept in imaging that describes the response of an imaging system to a point source or point object. It characterizes how a single point of light is...

A Huygenian eyepiece containing a pointer at its focal plane that is used -- when viewing an object through the eyepiece -- for specific designation.

A device attached to the end of an alignment telescope that detects and calculates a plane mirror's rotation axis that is perpendicular to the line of sight. The device is adaptable for evaluation of...

A stationary noise that occurs for visible light photodetection when a steady light source, such as a heterodyne reference beam or high background light, dominates the signal.

The determination of a substance's identity or quantity through the analysis of its optical rotation. For example, the examination of crystals and polymers under polarized infrared radiation is very...

A combination of a polarizer and an analyzer that is used to detect birefringence or rotation of the plane of polarization of materials placed between them. Useful for the determination of stress...

A polariton is a quasiparticle resulting from the strong coupling between photons (light particles) and certain types of excitations in a material, such as electronic excitations (electrons and...

A subsurface imaging technique based upon the polarization of light reflected off an object. The polarization of reflected light gives information about the object's absorption properties that...

Capability requirement for optical switches for transmission lines to process arbitrarily polarized light because of the rapid changes in the polarization state of light propagating in the fibers.

An optical device capable of transforming unpolarized or natural light into polarized light, usually by selective transmission of polarized rays.

A device that is used to produce or analyze plane-polarized light. It may be a Nicol prism or some other form of calcite prism or a polarizing filter.

A mold for glass or plastics often made of stainless steel to prevent pitting or oxidation in service. It is polished to the opposite curve of the surface that will be molded, and may be spherical or...

The process of forming a polisher by pressing it with an optical surface.

The optical process, following grinding, that puts a highly finished, smooth and apparently amorphous surface on a lens or a mirror.

Any of the numerous powders used for grinding and polishing glass, crystal or metal, the chief material being emery and carborundum for grinding, and rouge or the oxides of tin, cerium or other...

A substance that transmits the infrared, but which is too delicate or fragile to be used in the form of a single crystal. Instead, the pure material is finely ground, pressed to the required shape,...

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...

Polymers are large molecules composed of repeating structural units called monomers. These monomers are chemically bonded together to form long chains or networks, creating a macromolecular...

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....

The condition in which there are more atomic systems in the upper of two energy levels than in the lower, so stimulated emission will predominate over stimulated absorption. This condition may be...

A 45-90-45° reflecting prism whose surfaces form the 90° angle reflecting the light beam through a total angle of 180°. The corners of the prism are rounded to minimize breakage and simplify...

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...

Positioning generally refers to the determination or identification of the location or placement of an object, person, or entity in a specific space or relative to a reference point. The term is used...

A device designed to measure electromotive force or electrical difference potential.

A technique used in radiography to determine a crystal's structure by obtaining radiographs of it in powder form, normally by the use of a powder camera that forms an image of the crystal's x-ray...

With respect to a lens, the reciprocal of its focal length. The term power, as applied to a telescope or microscope, often is used as an abbreviation for magnifying power.

For a pulsed laser, the product of the energy per pulse (joule) and the pulse frequency (hertz); expressed in watts.

Power modulation refers to the intentional variation of power levels in a signal, often in the context of electronic communication systems. This modulation technique is used to encode information...

Laws that predict the maximum power output as a function of tube diameter for a hydrogen cyanide laser of a given discharge length and cavity losses, all other parameters being optimized.

Refers to the voltage and current necessary for the operation of circuit devices.

An accurately produced hole of any size and shape that is used as a masking device in an optical system. Pinhole apertures of accurate diameters often are produced by laser beam penetration or by...

A step before fusion splicing that involves cleaning the fiber end with low-current electricity.

When uncontrolled laser energy leaks from a laser cavity prematurely, it causes serious damage to optical components and significant downtime for repair.

A blank having basic surface curves attained by forming heat-softened glass that is pressed in a mold.

Injecting a gas (usually nitrogen) with a very low moisture content into the body of an optical instrument to create a positive internal pressure. This prevents the entrance of moisture, which could...

A set of three colored lights which, when mixed, give the sensation of white light. The set used in color television, for example, is red, green, blue (RGB).

The first-order spectrum formed by a diffraction grating.

The chromatic resolving power of a prism is invariably stated for the case in which parallel rays of light are incident on the prism, in which the prism is oriented at the angle of minimum deviation...

The ghost image formed by a prism.

A prism is a geometric optical element with flat, polished surfaces that refract light. It is typically a solid, transparent object with at least two flat surfaces that are inclined relative to each...

The spectrum formed by a dispersing prism or a dispersing prism system.

Acronym for profile resolution obtained by excitation. In its simplest form, probe involves the overlap of two counter-propagating laser pulses of appropriate wavelength, such that one pulse...

A probe card is a testing device used in the semiconductor manufacturing industry to evaluate and test the electrical characteristics of integrated circuits (ICs) on a wafer. Its primary function is...