Photonics Dictionary: R

Any of the many devices used to detect the presence of radiation from a specific region of the electromagnetic spectrum.

A device used to accelerate the electrons in a free-electron laser by channeling microwave energy into waveguide cavity assemblies.

A device used to measure the intensity of radiant energy.

A metal device of convex or concave curvature to which lens castings or semifinished lenses are cemented with only their edges in contact with the device.

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...

A device that changes the frequency of light by inducing the Raman effect on a beam passing through it.

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...

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 imaging technology, a device that converts raster or line-scan data to pixel form for further processing.

An electronic device that minimizes short-term drift effects and random measurement error inherent in alternate ellipsometric measurement of two signals.

A geometric representation of a light path through an optical device; a line normal to the wavefront indicating the direction of radiant energy flow.

A device that is used to determine the index of refraction of a gas or liquid through the interference patterns formed by two beams of light, one of which has been transmitted by the sample. A single...

In chemistry, a device in which a chemical reaction takes place. In electronics, a device that introduces reactance into a circuit.

RGB stands for red, green, blue, which are the primary colors of light used in additive color mixing. The RGB color model is widely used in various electronic displays, such as computer monitors,...

A device employed to identify toxic agents lingering on the ground or in the air from up to three miles away, by using laser beams to detect infrared light-absorption patterns that can be analyzed to...

A display device, such as a cathode-ray tube, that is located at some distance from the source generating the displayed information.

The degree to which a predetermined or previous setting of a positioning device can be duplicated by observance of the optical phenomena.

Loss mechanisms that degrade the performance of all thin-film optical devices by removing radiant flux out of the specular beams.

A device having electrical resistance and used in an electric current for purposes of protection, operation or control of current.

A resonator is a device or system that exhibits resonance, which is a phenomenon that occurs when an external force or stimulus is applied at a specific frequency, causing the system to oscillate...

A device that uses nematic liquid crystals sandwiched between fused silica substrates to change the phase of polarized light. The cell is tunable from half-wave to zero retardation because variation...

A reticle, also known as a reticule or graticule, is a pattern or set of markings placed in the focal plane of an optical instrument, such as a microscope, telescope, riflescope, or camera, to...

Retroreflection is a phenomenon in optics where light is reflected back toward its source, typically in a direction nearly parallel to the direction from which it originated. This occurs due to the...

A retroreflector is an optical device or structure that reflects incident light or electromagnetic waves back to their source, regardless of the direction from which the light approaches. Unlike...

A sequential scanning device, utilizing a revolving lens, in which the cathode-ray tube image is transformed into a circle of fibers. The rotating lens focuses each fiber successively on a multiplier...

A small erect-image telescope for use as a sighting device on a rifle. The chief requirement is a long eye relief to avoid damage to the eye due to recoil. The power may lie anywhere between 1 and...

A Risley prism, also known as a Risley prism pair or Risley rotating prism, is an optical device used for controlling the direction of a laser beam or other optical beam by independently rotating two...

A precision positioning device used to produce rotary motion.

A structured light device using a rapidly rotating laser to project a beam of light that appears to the human eye as a continuous circle; used as a reference marker on walls or landscape for...

A ruticon is an opto-electronic device in which light going through it can be modulated by an electric field. The intensity distribution of the resulting image can be precisely controlled....