Photonics Dictionary

Deep learning is a subset of machine learning that involves the use of artificial neural networks to model and solve complex problems. The term "deep" in deep learning refers to the use of deep...

For an optical table, the amount of displacement that occurs when a heavy load is placed or moved on the surface. To measure deflection under static load, a 113-kg (250 lb) weight is placed in the...

Use of a photoelectric receiver to sense an object's presence by detecting a small amount of the emitter's light that is diffusely reflected by the object.

A step-by-step method of reducing the amount of data in a digital video signal to transmit or store a high-quality image. The digitized picture is analyzed, and fine detail and redundant pixels,...

A scale located on the eyepiece focusing screw and used to measure the amount of defocusing of the eyepiece in diopters. The reciprocal of the image distance in meters is a measure of the amount of...

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 dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion, which is the phenomenon where different wavelengths of light travel at...

A spectrophotometer that measures the amount of ozone in the atmosphere through a comparison of solar energy at two wavelengths in the ozone's absorption band. This comparison is achieved by...

A mode of laser printing in which each pixel is printed four times, providing sharper lines and a continuous tone from one-quarter the amount of image data, compared with single-raster output.

For a detector, the amount of time alotted for the observation of one location.

A lens mounting with eccentric rings that may be rotated to shift the axis of the lens to a prescribed position.

A unit of energy equal to the amount of energy absorbed by one molecule of material undergoing a photochemical reaction, as determined by the Stark-Einstein law.

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 type of modulation spectroscopy that measures spectral reflectance or transmittance changes induced by applying a perturbing electric field. It can be performed in contactless modes with no special...

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...

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 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...

A telescope that is mounted on an equatorial mount.

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

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 amount of x-rays used to penetrate and diffuse a target sample undergoing electron-probe microanalysis.

The ejection of electrons from the surface of a solid by the absorption of a sufficient amount of photons.

The Faraday effect, named after the English scientist Michael Faraday, is a phenomenon in physics where the polarization plane of light is rotated when the light passes through a transparent medium...

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,...

A type of mirage that creates a distorted vertical image of relatively flat objects so that they appear as mountains, cliffs, columns or castles. The nonexistent mountainous region in the Arctic...

A property of optical fiber that results from thermal stresses during manufacturing and is defined as the amount of curvature over any specified length of fiber.

A fiber optic spectrometer is a device used for measuring the spectral content of light. It utilizes optical fibers to transmit light from a source to a spectrometer unit, where the light is...

A transformer that is designed to regulate the amount of current that passes through an electron tube's filament.

The distance between the locating surface of the lens mount and the image plane.

Nonimage-forming light, concentrated or diffuse, that is transmitted through the lens to the image. It is frequently the result of reflections from lens surfaces, a lens barrel, shutter or lens mount.

Fluence is a term used in various scientific and technical disciplines to describe the amount of something per unit area. The specific meaning of fluence can vary depending on the context in which it...

1. The sector of the Earth's surface registered upon a remote sensing device in a satellite. 2. The amount of space occupied by a component on the surface upon which it is mounted. 3. The space on an...

A phenomenon that occurs in WDM and DWDM systems when three closely spaced signal wavelengths near the zero-dispersion wavelength interact with each other, producing a fourth wavelength that...

Free-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the transmission of data using modulated beams of light through free space (air or a...

A Fresnel lens is a type of optical lens that consists of a series of concentric grooves or steps carved into a flat, thin piece of transparent material, typically plastic or glass. This design...

Fresnel reflection refers to the reflection of light at the interface between two different media with different refractive indices. This phenomenon was named after the French engineer and physicist...

Fusion ignition refers to the point in a controlled nuclear fusion reaction where the energy released by the fusion reactions becomes self-sustaining, leading to a continuous release of energy...

A galvanometric scanner, also known as a galvanometer scanner or galvo scanner, is a type of optical scanning device used to rapidly and precisely direct a laser beam or other light source to...

An optical mounting device that permits adjustment around two perpendicular and intersecting axes of rotation.

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or phosphoric oxides. Common window or bottle glass is a mixture of soda,...

A thermal radiation detector consisting of a small cell with a blackened plastic front face that bulges slightly when heat is received by it. The bulging tilts a small mirror, which, in turn, varies...

Transparencies that represent progressive steps in the amount of transmitted radiation for administering predetermined amounts of radiation to a radiation-sensitive substance. The steps are...

A gyroscope is a mechanical device consisting of a spinning disk or wheel mounted on a spinning axis in such a way that its orientation remains fixed regardless of any movement of its mounting...

A mount that uses a floating suspension and a motor-driven gyroscope to keep a motion picture or still camera at a set angle even though the camera is mounted in a place that subjects it to heavy...

A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a tungsten filament surrounded by a small amount of halogen gas, such as...

A lamp designed to emit a large amount of infrared radiation; used in applications requiring heat.

A device having a plane mirror so mounted that it can be set to reflect sunlight into a piece of laboratory equipment. It is driven by a clock to compensate for the sun's daily motion around the pole...