Photonics Dictionary: D

A detector array refers to a collection of individual detector elements arranged in a two-dimensional grid or matrix format. Each element within the array is capable of detecting electromagnetic...

A Dammann grating is a type of diffractive optical element (DOE) used to create an array of equally spaced, uniform-intensity spots or beams. It is named after its inventor, Dr. Herbert Dammann. The...

An accurate cathode-ray tube display used to provide visual representation stored in a computer for the interpretation and evaluation of the data.

A multidimensional array of values that is commonly used in programming to describe a time series of image data. Each dimension in the data cube represents a new attribute, while the cells of the...

The circuit that regulates an electron beam's deflection in a cathode-ray tube.

The progressive defocusing of a cathode-ray tube display image that occurs when the deflected electron beam impinges on the cathode-ray tube screen at a slant.

A metal coil or coils wrapped around the outside of the neck of a cathode-ray tube. Current passing through the coils produces a magnetic field, which can be used as an alternative to deflection...

A spatial light modulator consisting of a metallized polymer film stretched over an array of metal-oxide semiconductor field-effect transistors (MOSFETs). Each mirror element in the film can be...

The ray refracted by a sphere of transparent material that travels back as closely as possible to the original path formed by the incident ray.

A flanged or plain ring with a restricted aperture, located in an optical system at any of several points, that cuts off marginal light rays not essential to image formation. Diaphragms are used as...

An eyepiece used in a polariscope or polarizing microscope to give a comparison view of the same object under illumination by the two complementary rays of polarized light.

The formation of a fan of light or energy rays in a beam as the beam passes through an extremely narrow aperture.

A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel grooves or rulings. These rulings act as an array of closely spaced slits...

The technique by which an analog image is converted by any of several means into a finite array of points, each represented by some numerical value. Once created, this array can be the basis of a...

Medical diagnostic (x-ray) imaging using laser printers to produce high-resolution digital hard copy instead of film exposed by phosphor-intensifying screens, thus providing radiologists with greater...

A ray that travels from one point to another without being reflected or refracted.

The observation of a reproduced television picture on the face of a cathode-ray tube.

A cathode-ray tube in which secondary emission electrons form a display of high intensity.

A laser having a rod that is a stacked array of discs immersed in a transparent flowing coolant fluid. In this way, the cooling rate is increased, the temperature gradients are basically parallel to...

The observable illustration of an image, scene or data on a screen such as a console or cathode-ray tube, seen as a graph, report or drawing.

A visual display used with a computer to give access to the many elements of data as an array of points. With the display console, an operator may check information in the computer and change it if...

In image processing, modifying the dot that forms the image in order to simulate a series of gray tones.

1. In optics, the bending of rays away from each other. 2. In lasers, the spreading of a laser beam with increased distance from the exit aperture. Also called beam spread. 3. In a binocular...

A diverging lens is a type of lens that causes parallel rays of light to spread out or diverge. It is thinner in the center than at the edges and is commonly referred to as a concave lens. The most...

A scanning technique in optical character recognition in which an array of photocells is used to scan each character to determine its horizontal and vertical characteristics.

An imaging process, similar to specific Doppler mapping radar techniques, that utilizes a laser, an optical imaging system, and a line array of photodetectors and spectrum analyzers. The laser...

A device used to detect and measure the quantity of exposure to nuclear or x-ray radiation, and dependent on the fact that such radiation ionizes a gas.

A display format consisting of small light-emitting elements arranged as a two-dimensional array. Various elements are energized to depict a character. The typical matrix is 5 x 7 dots.

A measurement of the spatial resolution of a line or area array in an optical character recognition scanning device.

The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such as calcite, is placed between the eye and a pinhole in a card, two bright...

A cathode-ray tube that either splits an electron beam from one source or uses beams from two sources to produce two beams, each of which can produce separate traces, but which can overlap.

A form of prism invented by H.W. Dove. It resembles half of a common right-angle prism in which a ray entering parallel to the hypotenuse face is reflected internally at that face and emerges...

A type of mosaic detector array that combines features of scanning and staring sensors by using a small rapid scanning motion (see saccadic motion) over a few pixels at a time.