Photonics Dictionary: P

A device that responds to incident light but does not generate light.

A passive optical network (PON) is a telecommunications network architecture that uses optical fibers and passive optical components to provide high-speed broadband services to end-users. In a PON...

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;...

The branch of science that treats light as a wave phenomenon wherein light propagation is studied by wavefronts rather than rays, as in geometric optics.

The study of visual perception by the sense of sight.

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...

Plastic optical fiber (POF) is a type of optical fiber made from transparent plastic, typically polymethylmethacrylate (PMMA) or polycarbonate. Unlike traditional glass optical fibers, which are made...

Plastic optics refers to optical components or systems that are made from transparent plastic materials, as opposed to traditional optical components made from glass or other materials. Plastic...

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...

A crystal-based device that combines and adjusts the intensities of multiple wavelengths of laser light in order to obtain the desired output wavelength.

A photonic cavity, also known as an optical cavity, is a structure that confines electromagnetic radiation within a certain region or volume. It is typically composed of materials with different...

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...

1. In a photonic interconnect, the number of detectors in a given area. Detectors spaced too closely may give rise to crosstalk. 2. In the cross section of a fiber optic bundle, the ratio of fiber...

The condition in which the index of refraction in an optical fiber varies as a parabolic function of the radius.

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 saturated compound of carbon and hydrogen used as a liquid coating material for optical components in high-power laser applications. See liquid coating.

The optical phenomenon that causes relative motion between two objects when the eyepoint is moved laterally. When parallax appears in a telescope between the image and reticle, this indicates the...

Means of amplifying optical waves whereby an intense coherent pump wave is made to interact with a nonlinear optical crystal to produce amplification at two other optical wavelengths. See parametric...

A device using a parametric amplifier inside a resonant optical cavity to generate a frequency-tunable coherent beam of light from an intense laser beam of fixed frequency. This device is tuned by...

Characteristic of optical analyses that are limited to infinitesimally small apertures. Also called first-order or Gaussian optics.

A ray that behaves according to paraxial equations; one that lies close to and almost parallel to the optical axis.

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

In a fiber optic guided missile, the point at which the optical fiber pays out from the bobbin on which it is wound.

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...

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...

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...

An optical system used to examine the pharynx.

In optics and photonics, "phase" refers to a property of electromagnetic waves, such as light, that describes the position of a wave at a given point in time within its oscillation cycle. More...

The use of a reflective device, which can be fashioned from a variety of materials including gases, solids, dyes, aerosols, semiconductor crystals and plasmas, to replicate a laser beam by reversing...

Phase contrast microscopy is an optical microscopy technique that enhances the contrast of transparent and colorless specimens, making it possible to visualize fine details and internal structures...

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...

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...

A technique used to generate a phase shift between reference and sample light beams. The phase shift can be performed through the use of a mirror that is moved along the optic axis by a piezoelectric...

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...

Abbreviated PAI. An imaging modality with a hybrid technique based on the acoustic detection of optical absorption from endogenous chromophores or exogenous contrast agents. Light is absorbed by the...