Photonics Dictionary: D

A structural method of optical character recognition, used where the input media are variable, as in hand-written or multifont documents. A series of questions (such as "Does the character contain a...

A quantitative measurement of the coherence of a light source; equal to the visibility (V) of the fringes of a two-beam interference test: where Imax equals the intensity at a maximum of the...

The number of unique ways in which a part can move in an alignment system. In static alignment, there are six: one in the direction of and one in rotation about each of the X, Y and Z axes. In...

In printing, a translucent screen used with lenses to provide an even distribution of diffused light.

In a camera, the focusing of an image on the screen located at the camera's film plane. Once the image is in complete focus, the recording medium is inserted in place of the screen.

A CRT screen on which two phosphors differing in color and persistence are deposited.

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.

Any of the constants that relate the tendency of the director to remain parallel to restoring torques throughout the media. The three constants of importance in liquid crystal displays are: splay --...

1. An optical device used for projection of enlarged images of transparencies or lantern slides on a screen. 2. A device designed to hold and backlight transparencies so that their images can be...

A dichroic coating, also known as a dichroic filter or dichroic mirror, is an optical coating designed to selectively transmit or reflect certain wavelengths of light while simultaneously absorbing...

A dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that selectively reflects or transmits light based on its wavelength. Dichroic...

Differential interference contrast (DIC) microscopy, also known as Nomarski interference contrast microscopy, is an optical imaging technique used in microscopy to enhance the contrast of transparent...

The interference pattern formed by light waves diffracted at the edges of an object as seen on a screen placed in their path.

Light emitted by one or more sources and characterized by a high degree of scatter.

An optical diffuser is an optical component or material designed to scatter or diffuse light that passes through it. It is used to create a more even or uniform illumination, reduce glare, or soften...

A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film cameras, which use photographic film to capture and store images, digital...

Digital holographic microscopy (DHM) is an advanced imaging technique that combines holography and digital image processing to capture and reconstruct three-dimensional images of objects. This method...

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...

The logarithmic method of determining emulsion speeds developed by the German standards organization, Deutscher Normenausschuss, in which the speed of the emulsion is doubled for each increase of...

The degree to which a vision system is capable of sensing differences in light intensity between two regions.

Dispersion refers to the phenomenon where different wavelengths (colors) of light travel at different speeds when passing through a medium. This variation in the speed of light for different colors...

A measure of the dispersive properties of a glass. The relative dispersion is defined as: where C, D, and F refer to the material's index of refraction at the three chief Fraunhofer lines in the...

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.

Atmospheric aberration caused by the Earth's rotation; the degree varies from 0 at the poles to a maximum of 0.31 s of arc at other locations.

In the context of materials science and semiconductor physics, doping refers to the intentional introduction of impurities into a semiconductor material in order to alter its electrical properties....

A type of transversely excited laser with a uniform arc-free discharge of large cross-sectional area that can be scaled to very large systems.

A system for fabricating optical fiber, consisting of a furnace that heats the materials, a polymer coating stage, a capstan-pulling apparatus that free-draws the preform into a fiber and a drum on...

The subtractive imbibing process of transferring color prints on paper whereby the dyes from three separately prepared images are transferred to one sheet of paper to form the color print.