Photonics Dictionary

An assembly of multiple prisms that disperses incident light into its spectral components without deviating light at the central wavelength.

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...

A general-purpose lens, also known as the Celor lens, used widely in photography and commercial processing; it has the form of a triplet with a split flint element.

Double-clad fiber (DCF) is a specialized optical fiber that features two concentric cladding layers surrounding a core. The design of double-clad fibers allows them to be used in various...

The hardware for reading (and writing in devices so equipped) an optical mass data storage disk.

A gas laser equipped with Brewster windows and concave mirrors (having unlike reflective properties) at each end of the tube to produce two separate wavelengths at the same time.

Dual-axis laser is a laser device or system capable of emitting laser beams along two orthogonal axes (typically X and Y axes) concurrently. This allows for precise control and manipulation of the...

In electrical equipment, power variations that are temporary (as opposed to the permanent, cumulative effects of drift).

The auxiliary electrode in a photomultiplier that gives rise to secondary emission and amplification when bombarded by photoelectrons.

An edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the semiconductor chip rather than from the surface. Edge-emitting LEDs are...

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...

1. The branch of physics that deals with the use of electrical energy to create or manipulate light waves, generally by changing the refractive index of a light-propagating material; 2....

The ability of a device to operate without electromagnetically interfering with the operation of nearby equipment and without suffering disturbances from the electromagnetic fields in its designated...

Radiation emitted from vibrating charged particles. A combination of oscillating electrical and magnetic fields that propagates through otherwise empty space with the velocity of light. This constant...

An electromagnon is a quasiparticle excitation that combines aspects of both magnetism and electric polarization in a crystal lattice. Specifically, it refers to a collective excitation of spins and...

Any device in which the passage of electrons through a vacuum, gas or semiconductor is the principal means of conduction.

A special evacuated camera equipped with means for holding a specimen and bombarding it with a sharply focused beam of electrons. A cylindrical film is placed around the specimen to record the...

A method of thin-film deposition in which electrons boiled off a heated cathode are used to melt the coating material. If a multipocket crucible is used, many materials can be processed at the same...

The method by which photographic film is scanned by an electron beam. One technique uses the uniform light of a television screen, focused by a lens onto the processed film, as a means of creating a...

An electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find applications in various fields, including cathode ray tubes (CRTs), electron...

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....

The term "embedded laser" typically refers to a laser device that is integrated or embedded into a larger system or structure. In this context, "embedded" implies that the laser is an integral part...

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...

Emission spectroscopy is a technique used to study the emission of electromagnetic radiation (light) by atoms, molecules, or ions when they undergo transitions from excited states to lower energy...

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...

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,...

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...

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...

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...

An erbium-doped fiber laser (EDFL) is a type of laser that uses an optical fiber doped with erbium ions (Er³+) as the gain medium. These lasers are widely used in telecommunications, medical...

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 factor, F, indicating the increase in shot noise in an avalanche photodiode as compared with the ideal multiplier, which is noiseless. The noise, which results from variations in avalanche gains,...

An exciton is a quasiparticle that represents the bound state of an electron and a hole in a solid-state material, typically a semiconductor or an insulator. In simpler terms, an exciton is a paired...

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...

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...

Instruments used by ophthalmologists and optometrists to study the eye. There are, for instance, the ophthalmoscope to observe and photograph the retina; the retinoscope and optometer to determine...

A multiple-beam interferometer, usually consisting of two flat plates, with high reflective ability. The plates are set parallel to one another by spacers so that lightwaves may bounce back and forth...

The maintenance of the same scanning relationship between the transmitting scanning spot and receiving scanning spot for each scanning line transmitted in a facsimile system.

A FAC lens, or fast axis collimation lens, is an optical component used in laser diode systems to collimate the fast axis of laser emission. Laser diodes emit light in two main axes: the fast axis,...

The fiber optic connector standard for Nippon Telephone & Telegraph (NTT) installations, developed with Nippon Electric Co. (NEC).

A system designed to control the output quantity of a device by returning a portion of its output signal to its input. This results in the manipulation of the input quantity so that the desired...