Photonics Dictionary: R

The temperature of a complete radiator that has a total radiant emittance identical to that of an unknown resource.

A photographic camera and processing system used to form a usable record of the subject in a short time, usually a few seconds, for immediate analysis.

An optical system that is corrected for distortion and spherical aberration and therefore forms the image of a straight line as a straight line.

Rabi oscillations are a fundamental phenomenon in quantum mechanics that describe the periodic and reversible exchange of energy between two quantum states when subjected to an oscillating external...

The astigmatism in a lens system that results when light enters the system at an oblique angle.

An alteration in magnification from the center of the field to any point in the field, measured in a radial direction from the center of the field. Some radial distortion is inherent in most optical...

Also known as radiation thermometer. A pyrometer in which the radiant intensity from the source to be measured is used to calculate its temperature. The usual detector is a thermocouple, thermopile...

A radioactive element that is placed or injected into a system to obtain an autoradiogram of the system. It is used in a number of fields where standard methods of internal imaging, for example,...

Total number of characters available to each position of a digital numeric system.

When light is transmitted through matter, part of the light is scattered in random directions. A small part of the scattered light has frequencies removed from the frequency of the incident beam by...

Raman spectroscopy is a technique used in analytical chemistry and physics to study vibrational, rotational, and other low-frequency modes in a system. Named after the Indian physicist Sir C.V. Raman...

Essentially, noise that cannot be predicted. Therefore, even if the magnitude of sound or oscillation in a system is known at a given moment, random noise can change in a short time.

The third dimension (depth or Z-axis) in an imaging system.

1. An optical distance finder that depends on triangulation of two convergent beams on an object from disparate view points. 2. A device that depends on the measurement of time of wave travel from an...

A double meniscus system in which two achromatized meniscus lenses are arranged symmetrically on either side of the aperture stop, reducing or eliminating distortion, coma and lateral color.

Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally introduced into the crystal lattice of a material to modify its properties....

In a gas, the temporary drop in density caused by contact with a sound wave.

The pattern of lines traced by rectilinear scanning in display systems.

Raster scanning is a technique used in imaging and scanning systems to systematically capture and process information from a two-dimensional area or surface. It involves moving a sensor or scanning...

A graph of the intersections of a fan of rays with the final image plane, plotted as a function of the positions of the rays in the pupil of the system.

When a lens system with a circular aperture is free of aberrations, the image of a point object will appear as a disc of finite size surrounded by concentric rings. When two points are separated such...

A prism system designed to produce a very high dispersion of light.

In an optical data storage system, denoting the optical head's ability both to record information and to detect it for playback.

An image that is formed when rays emerging from an optical system all converge to a point on the optical axis. A real image can be seen on a screen in the image space of the given optical system.

The ability of a vision system to interpret an image in a short enough time to keep pace with most operations.

A detector and signal demodulator used in optical communications systems to receive a signal and often to translate it into an electronic signal.

Recombinase polymerase amplification (RPA) is a molecular biology technique used to rapidly amplify specific DNA or RNA sequences under isothermal conditions, meaning it does not require the...

A reconfigurable optical add-drop multiplexer (ROADM) is a key component in wavelength-division multiplexing (WDM) optical communication networks. It allows for flexible and dynamic routing of...

An image-forming system that uses mirrors rather than lenses. Such objectives are frequently used for astronomical telescopes and in ultraviolet microscopes.

The term reflective is an adjective that describes the ability of a surface or material to reflect light or other forms of radiation. It implies the capability of bouncing back or redirecting...

The ratio of the diameter of the entrance pupil in an optical system to the equivalent focal length of that system. The relative aperture is denoted as a fraction in which f, the equivalent focal...

The steady state of temperature exhibited by a material that has absorbed and emitted radiation equally.

A form of lens assembly used in a projection system to maximize efficiency and assure uniform illumination of the object being projected.

A lens or lens system used to transfer a real image from one point within an optical system to another, with or without magnifying it.

Remote inspection refers to the process of inspecting, evaluating, or monitoring assets, equipment, infrastructure, or systems from a distance, typically using remote sensing technologies and...

Remote sensing is a method of data collection and observation where information about objects, areas, or phenomena on Earth's surface is gathered from a distance, typically using sensors onboard...

1. In optics, the ability of a lens system to reproduce the points, lines and surfaces in an object as separate entities in the image. 2. The minimum adjustment increment effectively achievable by a...

A chart on paper or glass containing a series of sets of lines at progressively smaller spacing and used to ascertain the limiting number of lines per millimeter that an optical system is capable of...

A measure of an optical system's ability to produce an image which separates two points or parallel lines on the object. See Rayleigh criterion of resolving power.

Resonance can be defined in various contexts, including physics, chemistry, and music. Here are definitions for resonance in a few different fields: Physics: In physics, resonance refers to the...