Definitions: P

A semiconductor material used in photodetectors, sensitive in the infrared up to 5 µm.

Geometrical partition possible with a sphere that can be four, six, eight, 12 or 20 solid-angle wedges. Each platonic mass is made up of a given number of regular polygonal faces and is classified...

The property exhibited by certain birefringent crystals in which the degree with which they transmit polarized light is different, depending on whether the ray is ordinary or extraordinary. An...

Pluggable optics, also known as pluggable transceivers or optical transceivers, are modular devices used in optical communication systems to transmit and receive data over optical fibers. They are...

Philips trade name for a lead oxide low-light-level vidicon tube.

A mixture of ionized gas and metal vapor generated by impingement of the laser beam onto a material being welded or a weld joint. The plume causes absorption and/or scattering of the incident laser...

A transparent lead-lanthanum zirconate titanate ceramic with optical qualities that can be controlled by applying voltages to thin plates of the material.

The transition boundary between P-type and N-type materials in a semiconductor.

Discharge that results when a doped semiconductor crystal with a PN junction is charged with a low-voltage direct current. The dual process depends on excitation caused by electrical energy...

A device used to detect radiant energy by means of the thermal expansion of gas.

In optics, the Pockels effect refers to the phenomenon where the refractive index of a material changes in response to an applied electric field. This effect is utilized in Pockels cells, which are...

A Pockels cell, also known as an electro-optic modulator, is an optical device used to control the polarization of light by applying an electric field. It is named after the physicist Friedrich Carl...

A reference sphere used to represent all possible states of polarization. All linear polarizations will lie on the equator and circular polarizations will correspond with the poles. Named for the...

A point cloud is a set of data points in a three-dimensional coordinate system, where each point represents a specific location in space. These points are typically obtained through various sensing...

1. With respect to angular subtense, a source of light, such as a star, that is very small. In a lab, a point source may be simulated by imaging a large source onto and through a pinhole, or by...

An established point on which the observer's eye is focused.

In digital image processing, a subcategory of frame processing that transforms pixel brightness and contrast through use of a mapping function. Point processing can be single-image (simple contrast...

A lamp, usually incandescent, that has a very compact filament, permitting a greater concentration of emitted light, aided by the use of small apertures and appropriate reflectors.

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 crystal diode whose rectifying activity is determined by the touching of the crystal to a finely pointed wire surrounded by a material of opposite type.

A device used in solar systems to direct mirror-reflected sunlight to a heat absorber and heat-driven engine, which turns a generator to produce electricity.

A method of producing magnified images by x-rays. The specimen is placed close to a point source of x-rays; the magnification achieved is the ratio of source-image to source-object distance....

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.

Depicting one of the two ends of an axis of rotation.

A polariscope with a half-shade device and an angular scale generally attached to the analyzer. It is used to measure the rotation of the plane of polarization by materials placed within it. A...

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...

The measurement of the rotation of the plane of polarization of radiant energy, usually through the use of a polarimeter.

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...

Polarization refers to the orientation of oscillations in a transverse wave, such as light waves, radio waves, or other electromagnetic waves. In simpler terms, it describes the direction in which...

In passive optical components, loss that varies as the polarization state of the propagating wave changes. Expressed as the difference between the maximum and minimum loss in decibels.

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...

A photometer having a pair of Nicol prisms introduced into the beam from the brighter of two sources to be compared. Turning one of these polarizers reduces the beam to equality with the beam of the...

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.

Single-mode fiber that preserves the plane of polarization of the light launched into it as the beam propagates through its length. Also called polarization-maintaining fiber. The polarization is...

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

A coating made up of particular birefringent materials having polarizing properties. It may be used, in some cases, to replace Polaroid or polarizing prisms.

A filter that polarizes light passing through it. It is possible to fabricate sheets of plastic or gelatin that contain birefringent crystals so oriented as to pass only polarized light. Such sheets...

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.

The process of aligning the crystallites in a piezoelectric material by placing a large DC field across the element at an elevated temperature. The alignment of crystallites results in an increased...

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.