Photonics Dictionary

An atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical elements in a sample by measuring the absorption of light at...

A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material or a detector. The camera generally contains a lens of variable aperture...

Cathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the form of light, into an electrical signal. Photocathodes are components used in...

A fiber optic end plate constructed by drawing a bundle of parallel fibers embedded in glass and cutting it into thin slices. These slices are assembled in a plane and heated to produce a...

A vacuum tube with an electron gun at one end and a fluorescent screen at the other. Electrons emitted from a heated filament are accelerated by a series of annular anodes at progressively higher...

Colorless crystals used in photoelectric cells and for photosensitive material in cathodes.

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

A photocathode that exhibits maximum sensitivity in the blue and ultraviolet regions of the spectrum. The sensitivity is obtained by the exposure of a thin layer of antimony to cesium vapor at an...

A photoelectric detector consisting of a glass tube internally coated with a low conductance material. Voltage applied along the tube causes photoemission from the photocathode at the end of the tube...

The noise produced in a photodetector when the photocathode is shielded from all external optical radiation and operating voltages are applied.

An instrument that serves to produce an enlarged electron image on a fluorescent screen by focusing an infrared image of a distant object upon a photosensitive cathode.

The recording of the information contained in a modulated electron beam onto photographic or silicon resin-coated materials. A direct recording method involves the passage of the recording medium...

An electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find applications in various fields, including cathode ray tubes (CRTs), electron...

A nonmagnetic instrument utilizing an electrofocus and deflection tube with a photocathode for imaging purposes. The optical image is converted into a photoelectric output at the photocathode and is...

The face of a cathode-ray tube (CRT) that has a fiber optic sheet attached to its surface. The sheet's fibers are at right angles to the face, allowing the transmittance of the fluorescent trace...

An X-Y electrically addressable series of arrays with individual electron emitters bombarding a phosphor-coated transparent plate. The phosphor is induced into luminescence, similar to traditional...

A fluorescent screen refers to a phosphorescent or fluorescent-coated surface that emits visible light when exposed to other forms of electromagnetic radiation, such as x-rays or ultraviolet light....

A microscope that uses a flying spot scanner, directed through the eyepiece, as a light source to determine the features of a transparent specimen. The flying spot is modulated by the varying density...

1. In a cathode-ray tube, the glow surrounding a bright spot that appears on the fluorescent screen as the result of the screen's light being reflected by the front and rear surfaces of the tube's...

An optical system that superimposes a synthetic display providing navigational or weapon-aiming information on a pilot's or driver's field of view. The system includes a cathode-ray tube, collimating...

An electro-optic system using, in general form, an evacuated glass envelope with a semitransparent photocathode at one end and a luminescent screen at the other for the amplification of an optical...

A camera tube similar in design to the iconoscope. However, the image formed in the image iconoscope is projected on a photocathode that emits photoelectrons to be focused on a material, forming the...

An image intensifier, also known as an image intensification tube or image intensification device, is a specialized electronic device used to amplify low-light-level images to make them visible to...

A camera tube widely used in television broadcasting. It consists of three sections within a single vacuum envelope. 1. A photosensitive film sometimes called the photocathode. The scene to be...

An image converter that produces a visible image based on the infrared emittance of the object. The infrared energy is focused on a photocathode that emits electrons. These are accelerated and...

An intensified charge-coupled device (ICCD) camera is an advanced imaging device that combines the capabilities of both an image intensifier and a charge-coupled device (CCD) sensor to achieve...

Astronomical detector consisting of a photocathode isolated from the target by a coin value from which electrons are focused on a nuclear emission, producing tracks on the emission. Track density can...

The pattern, formed by a character generation cathode-ray tube system, in which the characters are made up of wave shapes synthesized by a series of sine and cosine terms.

A vacuum tube in which a magnetic field is superimposed onto the tube's electrical field. When the two fields are aligned, electrons from the photocathode are accelerated through the tube in a spiral...

A device to modulate spatially a collimated coherent beam of light with input data in optical data processing. It uses a photocathode mounted on a microchannel plate, which amplifies an electron...

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 photon-counting instrument for use in both space-borne and ground-based photometric and spectroscopic instrumentation. This style of detector is composed of opaque photocathodes for photon to...

A photocathode having a P-type semiconductor with a work function less than its bandgap. The photocathode can release a hundredfold increase of photoemission in the infrared region.

An instrument used to record rapidly varying currents or voltages. An oscillograph may consist of a cathode-ray tube oscilloscope with a camera attachment, or a mirror galvanometer with a lamp and...

A system in which a supplied signal causes the deflection of the electron beam in a cathode-ray tube, thus forming a visible trace on the phosphor screen of the tube and providing for examination of...

The responsivity of a photocathode to luminous energy equal to the ratio of the photoelectric emission to the incident luminous flux.

Photocathodes are specialized materials or surfaces that exhibit the photoelectric effect, wherein the absorption of photons leads to the emission of electrons. When photons with sufficient energy...

A cathode principally designed to emit a photoelectric current.

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

An electronic tube instrument in which the anode current varies with the intensity of light incident on the cathode.

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

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...

The photographic recording of data, in binary form, for storage in memory. Exposure is achieved by a cathode-ray tube or by modulating a continuous-wave laser beam with a Kerr cell, both relative to...

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

A planar photocathode and a planar phosphor screen mounted in a close-spaced parallel configuration in an evacuated enclosure so that the ensemble of photoelectrons emitted from each photocathode...