Photonics Dictionary

The angle between the most divergent rays that can pass through the lens to form an image. In a birefringent crystal light modulator or Pockels cell, the maximum angle in the incident light rays that...

A physical constraint, often a lens retainer, that limits the diameter of the axial light bundle allowed to pass through a lens.

An apochromat, often referred to as an apochromatic lens or apochromatic objective, is a type of optical system designed to minimize chromatic aberration. Chromatic aberration occurs when different...

An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical lenses, which have a constant curvature across their surfaces, aspheric lenses...

An atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical elements in a sample by measuring the absorption of light at...

An autocollimator is an optical instrument used for measuring small angular deviations with high precision. It operates on the principle of autocollimation, where a light source is directed onto a...

A system for automatic industrial process control or measurement, consisting of an optical module for image acquisition, a segmentation processor to isolate the image from its background, and an...

A negative lens used to increase the effective focal length of a telescope objective.

The negative distortion that causes a square grid pattern to be imaged as barrel-shaped.

A beamsplitter is an optical device for dividing a beam into two or more separate beams. beamsplitter suppliers → A simple beamsplitter may be a very thin sheet of glass inserted...

An experimental lens used to produce interference fringes. A positive lens is cut into halves along its center, and the halves are separated. This produces a double image of a slit source set...

A type of piezoelectric translator that uses two thin strips of piezoelectric material, one expanding while the other contracts, to produce movement.

A microscope designed with two eyepieces (oculars), permitting the use of both eyes when viewing through the instrument.

A term pertaining to devices (generally optical) designed for use with both eyes viewing through a single exit pupil. The term may be distinguished from binocular in that biocular instruments contain...

Birefringence is an optical property of certain materials that causes them to exhibit different refractive indices for light of different polarizations. In other words, when light passes through a...

A source that attempts to create the characteristics of an ideal blackbody. It consists of a cavity, generally spherical, made of an opaque material and insulated from thermal effects, with a small...

An apparatus, designed for use with a camera, that is used to rapidly open the path from lens to film, to maintain the opening throughout exposure and to close the opening in rapid succession. The...

A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material or a detector. The camera generally contains a lens of variable aperture...

A two-mirror lens design used in astronomical telescopes, the primary being a parabola, the secondary a smaller hyperbola. The image formed is free of spherical aberration and color and is located...

A charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital cameras, camcorders, and scientific instruments. It consists of an integrated...

The ray that passes through the center of the aperture stop in an optical system. It often is called the principal ray of an oblique beam.

That part of an infrared detector-Dewar assembly that limits the solid angle viewed by the sensor; it is maintained at a uniformly cold temperature so that no thermal energy is emitted. Also known as...

A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides objective and standardized color information, typically expressed in terms...

A lens aberration, resulting from different magnifications in the various lens zones, that occurs in that part of the image field that is some distance from the principal axis of the system....

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator configuration used in laser systems. The term confocal in this context refers to the...

Hardware installed on fiber cable ends to provide cable attachment to a transmitter, receiver or other cable. Usually a device that can be connected and disconnected repeatedly.

A lens aberration in which the focal length varies radially outward from the center of the field. It has the effect of making a straight tangential line in the object appear curved in the image,...

Deep ultraviolet (DUV or deep-UV) refers to a specific range of ultraviolet light with shorter wavelengths than those in the UV-A and UV-B regions. The exact wavelength range considered as DUV can...

A detector-Dewar assembly typically refers to a combination of a detector and a Dewar flask used in scientific instruments, particularly in the field of infrared spectroscopy or other applications...

As a wavefront of light passes by an opaque edge or through an opening, secondary weaker wavefronts are generated, apparently originating at that edge. These secondary wavefronts will interfere with...

A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel grooves or rulings. These rulings act as an array of closely spaced slits...

A cosmetic defect on the surface of an optical element. A dig is nearly equal in terms of its length and width. The size is specified numerically by its average diameter in 1/100 of a millimeter;...

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

The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such as calcite, is placed between the eye and a pinhole in a card, two bright...

A refracting telescope that uses a prism to bend the line of sight 90°.

A lamp that uses the transmission of an electric current through a gas or vapor to produce illumination. Neon, mercury and argon lamps are examples of electric-discharge lamps.

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 device utilizing an electron beam for the observation and recording of submicroscopic samples with the aid of photographic emulsions or other short-wavelength sensors. With the electron microscope,...

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 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...