Photonics Dictionary

An electron tube having a photocathode for the emission of a photoelectric current.

A photoelectrical relay that uses a phototube as its photoelectric device to open and close an electrical relay; used to activate counters and safety controls.

A phototube having a cesium-coated cathode that has its greatest sensitivity in the infrared region.

A phototube having increased response due to the addition of a quantity of gas.

A device designed to detect microwave modulation and to mix modulated and unmodulated laser beams. It consists of a photosensitive cathode and a microwave-electron-tube structure that amplifies,...

A traveling wave tube (TWT) containing a photocathode and window that, receiving a laser beam, produces a modified photoelectric current that is accelerated and propagated into its helical frame.

A phototube that functions within a vacuum and thus eliminates the effects of gaseous ionization on its electrical properties.

A phototube in which the primary photoemission current, before being extracted at the anode, is multiplied many times.

A device that detects radiation by utilizing the influence of light in forming an electrical signal. It may be a phototube; a photoconductive, photovoltaic or photojunction cell; a phototransistor;...

The increase in current of a phototube as a result of the gas in the tube becoming ionized.

A device using the Kerr effect to read back the signals from mechanically recorded tapes and discs. It consists of a light source, optical lenses to focus and direct the light beam, a pair of...

An electrode used to release photoelectric emission when irradiated, making it then the irradiated negative electrode of a phototube.

The electron stream emitted by a phototube when the cathode is exposed to light.

Also known as electronic photometer. A photometer with a photocell, phototransistor or phototube for measuring the intensity of light.

A system mounted a few inches above a moving plane that consists of a light source, lenses and one or more phototubes. In this position, the scanner actuates the control equipment when the quantity...

A particular type of phototube having increased sensitivity as a result of the glow initiated by light incident to the cathode.

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 device composed of a light source and phototube used to scan a moving strip of material in photoelectric side-register control systems.

A photofluorescent compound that, when used with a scintillating substance, absorbs photons and emits related photons having a greater wavelength. In this way a phototube or photocell may employ the...