Photonics Dictionary: E

A characterization of the throughput performance of data storage systems; the EDR is the total of data retrieved divided by the total time it takes to retrieve it, expressed as megabytes per second.

Expression of the length of a transmission medium in terms of wavelengths of the propagating wavelength. In general, electrical length is an expression of physical length in wavelengths, radians or...

An electro-optic deflector is a device that can change the direction of light beams using an electric field. It operates based on the electro-optic effect, which involves the modulation of the...

An EMCCD (electron-multiplying charge-coupled device) camera is a type of scientific camera specifically designed for low-light imaging applications that require high sensitivity and fast readout...

An electron-beam lithography (EBL) system is a sophisticated nanofabrication tool used in the semiconductor industry and research laboratories to pattern extremely fine features with sub-micrometer...

A mechanical shutter that has had its timing escapement replaced with an electronic timing circuit. This circuit allows a wider range of exposure times, can be more accurate, and, placed in a circuit...

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

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...

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.

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.

The amount of energy required to raise the energy level of an atom; a necessity if the atom is to radiate energy. High excitation potential is the amount of energy in the upper state of the...

The light spectrum formed by an explosive reaction or by the electrical explosion of a metallic wire by a strong current.

In cosmology, a star that exhibits a rapid increase in the magnitude of light, which is followed by a slow decrease in magnitude. The nova and supernova are explosive variables.

In optics, the total radiant energy incident on a surface-per-unit area. It is equal to the integral over time of the radiant flux density. Also known as radiant exposure.

A measure of film speed sensitivity to light.

An instrument used to measure the light from a scene to be photographed and to indicate the camera lens and shutter settings required to expose the film correctly. The exposure time required in a...

The length of time during which the receiver is irradiated.

1. A strainmeter capable of measuring the change in the relationship between two reference points, provided that the points are separated by at least 20 to 30 m. 2. An instrument used to determine...

A type of exposure meter that artificially reduces the light admitted in a sequence of known fractions until a value is reached that is equivalent to the proper exposure.

Extreme ultraviolet (EUV) refers to a specific range of electromagnetic radiation in the ultraviolet part of the spectrum. EUV radiation has wavelengths between 10 and 124 nanometers, which...

Wavelengths between 400 and 1400 nm (VIS to NIR) are focused onto the retina by the cornea. Because the retina is sensitive to light, these wavelengths can be damaging even at low energies. It is the...