Photonics Dictionary: C

In an interferogram, an intense portion of the recording that corresponds in size to the amount of infrared radiation incident on the detector.

The surface curvature designed to reduce the marginal error found in the periphery of a spectacle lens.

1. Mounting a lens or mirror so that its optical axis is coincident with the optical or mechanical axes of other portions of the system. 2. The machining (edging) of the outside diameter of a lens...

In the SI system, prefix meaning one hundredth, 10-2.

In a reflecting telescope, the obstruction of the primary mirror by a secondary mirror which blocks a small amount of the light reflected by the primary mirror and introduces additional diffraction.

The computer module whose circuitry interprets instructions and guides the actions of the peripherals. Also known as the mainframe.

In a perfectly centered lens, the mechanical axis (defined by the ground outside the diameter of the lens) is made to be exactly coincident with the optical axis (defined by a line through the...

A rotating chamber that can be spun at different speeds to generate great radial forces used to simulate different gravity loads.

A microscope that can be used to observe and magnify microscope specimens while they are being centrifuged. The objective rotates near the periphery of the centrifuge head, and the ocular is...

An instrument that detects high-energy charged particles by analysis of the Cerenkov radiation that they emit.

The radiation produced when a charged particle traverses a medium that has a refractive index considerably greater than unity. The moving particle has a velocity that exceeds the velocity of light in...

A polishing material that has a quicker polishing action than rouge (ferric oxide) and that is cleaner to handle.

An isotope of cesium that emits negative beta particles and has a half-life of 2.19 years; its applications include photoelectric cells and developmental ion propulsion systems.

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

A photoemissive detector sensitive to wavelengths up to 1 µm. It has one sharp maximum of sensitivity at 350 nm and a broad maximum at 800 nm.

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

A lamp that emits light as the result of the passage of an electrical current through ionized cesium vapor.

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...

The breakdown of the bonds in polymer chains caused by illumination.

Chalcogenide refers to a class of compounds containing elements from group 16 of the periodic table, which includes sulfur (S), selenium (Se), and tellurium (Te). These elements are known as...

Proprietary name for a low-light-level TV pickup tube.

The removal of sharp edges by grinding.

The number of channels per unit bandwidth handled by a single optical fiber.

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 parallel resistance and capacitance appearing between the active guard ring junctions in a silicon photodiode.

The creation of a diode laser structure by liquid-phase epitaxy over a grooved substrate.

A cathode-ray tube that generates symbols for use in other displays. The tube operates by scanning specific characters on the target and generating them as video signals to other cathode-ray systems.

Computer hardware or firmware that accesses character patterns stored in read-only memory and displays them at specific coordinates on a screen.

A photoelectrically controlled, alphanumeric reading device that converts characters to audible or sorting signals which can be fed to a computer, electric typewriter, tapepunch or other machine.

The angle at which a given mode propagates down an optical fiber.

A graph used in photography to portray the increase of a film's density as its time of exposure increases.

In a charge-coupled device, the disappearance of some of the accumulated charge into the silicon during readout.

A charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital cameras, camcorders, and scientific instruments. It consists of an integrated...

A charge-injection device (CID) refers to a class of devices that manipulate and detect electrical charge within a semiconductor material. Charge-coupled devices are a specific implementation of this...

See charge-coupled device; charge-injection device.

In a charge-coupled device, the percentage of each charge packet that is carried over to the next stage of the transport shift register.