Photonics Dictionary

An aberration sensor typically refers to a component or feature in optical systems, especially in telescopes or cameras, that detects and quantifies aberrations. Aberrations are imperfections or...

An achromat, in the context of optics, refers to a type of lens or lens system designed to reduce chromatic aberration. Chromatic aberration is an optical phenomenon where different colors of light...

An achromatic lens is a type of optical lens designed to minimize chromatic aberration, which is the inability of a lens to focus all colors of light to the same convergence point. Chromatic...

Achromatism refers to the optical property of a lens, prism, or optical system that minimizes or eliminates chromatic aberration. Chromatic aberration is the phenomenon where different wavelengths...

Actinic focus refers to the point or plane within an optical system where ultraviolet (UV) light or other actinic radiation converges to form the sharpest possible image. Here are the key aspects: ...

Active optics refers to a technology used in telescopes and other optical instruments to improve the quality of images by dynamically adjusting the shape of optical components, such as mirrors, in...

Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of atmospheric distortions. The Earth's atmosphere can cause light passing through it...

An optical tooling instrument consisting of an objective lens, a focusing lens, an optical micrometer, a reticle and an eyepiece. The alignment telescope projects a precise line of sight to which a...

An antireflection coating (AR coating) is a thin film or coating applied to optical surfaces, such as lenses or windows, to minimize unwanted reflections and increase the transmission of light...

An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and coma. Spherical aberration is an optical aberration that occurs when light rays...

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 aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical surface profile. Unlike traditional spherical mirrors, which have a curved...

An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It serves as the primary optical element responsible for gathering and...

An astronomical telescope is a type of optical instrument designed to gather and magnify light from distant celestial objects for observation and analysis. It typically consists of two main optical...

A low-power telescope placed at the eyepiece of an optical system to increase overall magnification. Most often used to evaluate image quality.

Binoculars are optical instruments used for magnifying distant objects by using two parallel telescopes mounted side by side. They allow users to see distant objects more clearly and in greater...

A device for the internal inspection of hard-to-get-at mechanical parts, such as rifle barrels, sewer pipes, oil wells, or gas mains. The long narrow tube used contains a telescope system with as...

Catoptrics is the field of optics concerned with the reflection of light from reflective surfaces such as mirrors. It encompasses the study and analysis of how light rays interact with these...

Centration is the precise alignment of the optical center of a lens or optical element with its mechanical center or the axis of the mounting assembly. It is crucial for ensuring that the optical...

Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a lens or optical system, leading to a failure to focus all colors to the same...

An optical instrument used to track and image a test vehicle (target) throughout its flight. The cinesextant frequently includes multiple devices such as high-speed video and film cameras as well as...

Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In the context of geometry or optics, a concave shape is one that curves or...

Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These mirrors are commonly used in optics for various applications, including...

Diamond turning refers to a precision machining process used to produce complex optical components, particularly lenses and mirrors, from materials such as metals, plastics, and crystalline materials...

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 defect of a binocular instrument causing two images to be seen separately instead of being fused. It is caused when the optical axes of the two telescopes are not parallel. In minor cases, the eyes...

The field of view (FOV) refers to the extent of the observable world or the visible area that can be seen at any given moment through a device, such as an optical instrument, camera, or sensor. It is...

Freeform mirrors refer to reflective optical components that deviate from traditional symmetric or rotationally symmetric shapes, such as spheres or paraboloids. Unlike conventional mirrors, which...

Freeform optics refers to the design and fabrication of optical surfaces that do not follow traditional symmetric shapes, such as spheres or aspheres. Unlike standard optical components with...

Any form of lens, optical system (camera, telescope, microscope, etc.), or opto-electronics utilized for the purpose of producing an image of a given object.

An optical instrument containing a gimballed sighting telescope, used to measure angular relationships in horizontal and vertical planes.

A small defocused Galilean telescope mounted in a hole in a door. Viewed from inside through the positive lens, a wide-angle view of the outside is seen; viewed from outside through the negative...

An artificial star used to aid in adaptive optics imaging of the sky. The guide star is provided from a telescope system on the ground and is directed into the imaged region. The wavefront...

A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which lenses are eventually fabricated. Lens blanks are made from various...

A lens is a transparent optical device that focuses or diverges light, allowing it to pass through and form an image. Lenses are commonly used in optical systems, such as cameras, telescopes,...

The line of vision; the optical axis of a telescope or other observation system. The straight line connecting the object and the objective lens of the viewing device.

A liquid crystal light valve (LCLV), also known as a spatial light modulator (SLM), is an optical device that modulates the intensity, phase, or polarization of light passing through it using liquid...

Liquid or fluid optics refers to the use of liquids to create or enhance optical systems. These systems leverage the unique properties of liquids, such as their ability to change shape, refractive...

The ability of an optical system to make an object appear larger. An optical element or optical system causing an object to appear twice as high and twice as wide is said to have a magnification of...

A wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that produced by the other telescope, thus affording a measurement of the...

A meniscus lens is an optical lens that has one side that is concave (curved inward) and the other side that is convex (curved outward). It can be categorized into two types based on its optical...

A mirror blank refers to the initial piece of material from which a mirror is made. It is typically a flat or slightly curved piece of glass or other substrate that serves as the starting point for...

A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are essential components in optical setups for reflecting light or redirecting laser...

MTF analysis/measurement equipment refers to instruments and tools used to measure and analyze the modulation transfer function (MTF) of optical systems. The MTF is a quantitative measure of the...