Photonics Dictionary: E

In photography, the layer of light-sensitive material (usually a suspension of silver halide crystals) that coats the film or plate.

The sensitivity of a photographic emulsion when exposed to light, provided that the film is developed through a standard process.

A molecule that is the mirror image of another molecule. The two mirror-image molecules have the same chemical properties; their behavior differs only in reactions with other enantiomers or with...

An arc lamp whose carbon electrodes are enclosed in a transparent chamber, resulting in an arc that is steadier, lasts longer and emits more ultraviolet radiation.

A laser or laser system positioned within an enclosure to prevent dangerous optical radiation from leaving the enclosure.

End-fire coupling refers to a method of coupling energy into or out of a waveguide, transmission line, or antenna, where the electromagnetic waves are directed primarily along the axis or direction...

An endoscope is a medical device used for visualizing and examining the interior of hollow organs, body cavities, or confined spaces within the body. It consists of a flexible or rigid tube equipped...

A hologram produced by a pair of radiation beams, each carrying information.

The occurrence of very large rotations in transparent materials at weak magnetic fields as predicted in the classical dispersion theory. This effect was discovered by Mavaluso and Corbino in 1898 in...

Enhanced picture archiving and communication system (PACS) display (ePAD) is a software tool used in medical imaging to view, manipulate, and analyze radiological images, such as x-rays, CT scans,...

The entrance slit, also known simply as the slit, is an essential component in optical instruments such as spectrometers and monochromators. It is a narrow opening or aperture through which light...

Distortion caused by variations in the rate of change of phase shift with frequency over the signal's necessary bandwidth.

A test chamber designed to expose the subject being tested to external conditions, such as heat, shock, pressure and moisture, for the study of their effects.

Potential hazards to a system's application and installation, including temperature variations, chemical reactivity, mechanical stress and moisture.

The maximum to minimum range of temperature, pressure, humidity, vibration and biological conditions under which an optical component or system can function and be stored. The range required depends...

An enzyme-linked immunosorbent assay (ELISA) is a laboratory technique used to detect and measure the presence of specific substances, such as antibodies, antigens, proteins, hormones, or other...

A tabulation of predicted positions that have been calculated for one or more celestial bodies or orbiting satellites.

Fluorescence imaging technique in which the excitation light from the objective is directed into the sample producing emission at all angles. Light emitted into the objective is measured allowing the...

Epitaxial refers to the growth of a crystalline layer on a crystalline substrate in such a way that the orientation of the crystal lattice of the growing layer is related to that of the substrate. In...

Epitaxial deposition is a process used in semiconductor manufacturing and materials science to grow a thin crystalline layer, known as an epitaxial layer, on a substrate. The term epitaxial refers to...

Epitaxial equipment refers to a set of specialized tools and systems used in the process of epitaxy, which is the growth of crystalline layers on a substrate material. Epitaxial growth is a critical...

A well controlled thin films technique for growing films with good crystal structure in ultra high vacuum environments at very low deposition rates. Epitaxy methods are well known for the growing of...

Common name for a variety of adhesives used for lens bonding, fiber optic splicing and other photonics applications. The term is actually a prefix denoting the presence of an epoxide group in a...

A stimulus that contains equal energy at each wavelength in the visible region of the spectrum.

A densitometer having a receiver that indicates when a desired radiation level has been attained.

A telescope stand equipped with a polar axis that can be set parallel to the Earth's axis of rotation and a declination axis that is at right angles to the polar axis. If the telescope is turned at a...

1. A contour map of a photographic deposit consisting of lines and curves that join points of equal density. 2. The portrayal of a photograph's points of equal density in hues of yellow, cyan and...

The length of optical waveguide needed to attain equilibrium mode distribution for a specified excitation condition.

The condition in a multimode optical waveguide in which the relative power distribution among the propagating modes is independent of length.

Calculation of the amount of energy extracted from a light beam regardless of its wide range resolution.

When a block of glass (prism, window, filter, etc.) is placed into a converging light bundle, it increases the physical distance to the point of focus. The equivalent air path for that block of glass...

An Er:YAG laser is a type of solid-state laser that uses a crystal made of erbium-doped yttrium aluminum garnet (Er:Y3Al5O12) as the gain medium. The erbium (Er) ions are introduced into the crystal...

Data or encoded information capable of being eradicated, leaving the media free for rewriting. Also called reversible.

An optical fiber that can be used to amplify an optical input. Erbium rare earth ions are added to the fiber core material as a dopant in typical levels of a few hundred parts per million. The fiber...

An image, real or virtual, whose spatial orientation is identical to that of the object. The image obtained at the retina with the assistance of an optical system is said to be erect when the...

In image processing, a morphology operator in which a structuring element or probe of a particular shape is moved over the input image. Where the probe fits completely within the boundaries of a...

The addition to the information signal in communications of redundant bits that enable the originally encoded message to be decoded without degradation of the data. In compact disc technology, the...

A single number, defined by the computer program or the user that expresses the performance of an optical system. Also known as merit function and defect function, the error function comprises...

Localized redness of skin due to congestion of capillaries; a common result of overexposure to laser radiation.