Photonics Dictionary: E

Observed phenomenon of a small developed image with higher density than a larger image because of variation in photographic plate densities with variations in size of opening.

The real numerical aperture (NA) of a fiber when the computed NA is not valid because of change in the glass indices during drawing and fusion.

Scattering caused by the interaction between ingoing and outgoing particles of the same type, with no loss of kinetic energy.

A change in the refractive index of an optical fiber caused by variation in the length of the fiber core in response to mechanical stress.

An electrically excited laser having carbon monoxide as the lasing material and in which lasing occurs in a partial inversion between adjacent, vibrational fields. Vibrational energy is cycled...

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 electro-optic modulator (EOM) is a device used to modulate the amplitude, phase, or polarization of light waves using an external electrical signal. Electro-optic modulation is a fundamental...

A type of optical modulator with potential application in optical switching and displays, in which applied voltage causes a change of interfacial tension between mercury and an electrolyte, varying...

A spectrum band that is usually found in the visible or the ultraviolet because of the electron transitions taking place within the molecules.

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...

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 movement of particles or ions in a solution toward the electrode having the opposite sign because of the application of an electrical field.

An electrophoretic display, often referred to as an electronic paper display or e-paper display, is a type of electronic visual display technology used in electronic devices for the purpose of...

Elastic deformation of a dielectric caused by volume force when the dielectric is placed in an inhomogeneous electric field.

An electrowetting display (EWD) is a type of electronic display technology that utilizes the principles of electrowetting to control the behavior of colored oil droplets on a hydrophobic surface....

Embedded vision refers to the integration of computer vision technologies into various embedded systems, devices, or machines. Computer vision involves teaching machines to interpret and understand...

Thermal emission caused by the unity in absorption bands that must be discriminated when calculating radiation intensity of any celestial object.

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...

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

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...

An etalon is an optical device that consists of two parallel reflecting surfaces separated by a precise and known distance. It operates based on the principle of optical interference and is used to...

Etaloning is an optical phenomenon that occurs in imaging systems, particularly in devices such as spectrometers, interferometers, and cameras. It is characterized by the appearance of interference...

A high-frequency approach to the propagation of light in graded-index fibers in which the modal field is represented in terms of an inhomogeneous (evanescent) plane wave with a complex phase, so that...

Coating carried out in a sealed chamber evacuated by a mechanical pump in series with an oil diffusion pump to a pressure less than 10-4 mm of mercury, measured by a vacuum gauge. At such a low...

An event-based image sensor, also known as a dynamic vision sensor (DVS), is a type of digital imaging device designed to capture visual information in a highly efficient and unique way compared to...

Excimer laser coronary angioplasty (ELCA) refers to a medical procedure used in the treatment of coronary artery disease. This technique involves the use of an excimer laser to perform angioplasty, a...

A small incandescent lamp whose intense beam is focused on the optical soundtrack of a motion picture film. The soundtrack modulates the beam, which in turn is detected by a photocell that produces...

Photoconductivity due to the addition of impurities or external causes.

A pattern on an oscilloscope display that consists of a string of shapes that resemble eyes. Because the pattern becomes more closed with increasing distortion and interference, an open eye diagram...

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...