Photonics Dictionary: R

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 type of camera that incorporates a tiny mirror that oscillates in accordance with incoming signals. An illuminated slit is imaged by this tiny mirror on a moving ribbon of sensitized paper or film,...

A solar spectrograph that uses long focus concave mirrors as its collimator and camera element.

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...

Two lenses, separated by a distance equal to the sum of their focal lengths, and retroreflecting mirror assemblies, one of which is coaxial with the lenses and the other slightly translated off-axis.

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 corrective lens system that is placed near the focal plane of a Newtonian telescope to increase its effective field of view by correcting for coma formed by the telescope's paraboloidal mirror.