Photonics Dictionary

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...

In color perception and vision an achromatic point refers to a color stimulus that appears neutral or without hue, often perceived as a shade of gray. It represents a point in color space where the...

An achromatic prism is a type of prism designed to separate white light into its component colors (spectrum) without causing chromatic aberration. Unlike regular prisms, which disperse light but also...

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...

Acousto-optics is a branch of physics that deals with the interaction of sound waves (acoustic waves) and light waves (optical waves) within a medium. It primarily focuses on phenomena where acoustic...

Actinochemistry refers to the branch of chemistry that studies the chemical effects of radiation, particularly light, on substances and chemical reactions. Here are the key aspects of...

An actinometer is a device used to measure the intensity of radiation, particularly solar radiation or light, often with a focus on its ability to cause photochemical reactions. Here are the key...

Actinometry refers to the measurement of the intensity of radiation, particularly light, with a specific focus on its ability to cause photochemical reactions. It involves quantifying the amount of...

An active infrared (IR) system is a type of technology that uses infrared radiation actively emitted and detected by sensors for various purposes. Here are the key features and applications of active...

An actuator is a mechanical or electromechanical device that is responsible for moving or controlling a mechanism or system. It converts various forms of energy (such as electrical, hydraulic,...

Visual acuity specifically refers to the clarity or sharpness of vision, typically measured by the ability to discern the details of objects at a specific distance. It is a fundamental measure of the...

Acutance refers to the perceived sharpness of an image in terms of the contrast of edges, rather than the resolution of fine details. It relates to how well-defined and crisp edges appear in a...

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...

The advanced communication technology satellite (ACTS) was a program developed by NASA (National Aeronautics and Space Administration) in the United States to demonstrate and advance satellite...

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...

Charged frozen pellets that are rapidly bombarded with a focused high-power laser to form a dense plasma that can be heated and sustained with neutral beams.

An angle formed by the lines of sight of both eyes when focusing on an object. Also, the rate at which a ray approaches the optical axis.

Also known as a shadow mask, a perforated plate placed between the focusing and accelerating electrodes, and the tricolor phosphor screen in a color-television tube.

Aplanatic points refer to specific points in an optical system where certain aberrations, such as spherical aberration or coma, are minimized or eliminated. In an optical system, aberrations are...

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 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 argon-fluoride (ArF) excimer laser is a type of ultraviolet laser that operates using a mixture of argon and fluorine gases. Excimer lasers are a class of gas lasers that emit light in the UV...

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...

In an astigmatic grating, the image of the entrance slit located at the primary focus.

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 spectrograph in which the refracted beam returns almost along the path traveled by the incident beam, and is brought to a focus by the lens that collimates the incident beam.

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 lens aberration that causes axial light rays having different wavelengths to focus at various points along the axis.

An axicon is a type of optical component characterized by its conical shape and its ability to transform a collimated Gaussian beam of light into a ring-shaped beam with a gradually increasing...

A ball lens is a small, spherical optical component typically made of glass or other transparent materials. It is characterized by its spherical shape, with both its front and back surfaces forming...

Beam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It involves measuring and visualizing how the optical power or intensity is...

A beam shaper is an optical device or system designed to modify the spatial profile or intensity distribution of a laser or light beam. The goal is to transform the incoming beam into a desired shape...

A band of light that appears along the outer edge of a transparent material under microscopic investigation and that moves toward higher refractive indices as the microscope's focus is raised, and...

A small convergent lens, located between the objective and eyepiece of a microscope, that focuses an image of the upper focal plane of the objective in the focal plane of the eyepiece. It is commonly...

A device having a pair of decentered lenses, one for each eye, that focuses on a single object as a magnifier. It is often supplied with a forehead fixture or an elastic headband to leave the hands...

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...

Also called proximity focus image intensifier. A compact image intensifier that utilizes a microchannel plate intensification stage. This is an in-line device that does not invert the image.

The loss of focus of a camera sensor because of excessive brightness, characterized by the enlargement of spot size and halation on a cathode-ray tube.

A blur circle refers to the out-of-focus region in an image captured by an optical system. When an object in a scene is not in perfect focus, its image is spread out into a circular shape on the...

Brillouin microscopy is a non-invasive imaging technique that utilizes Brillouin scattering to measure the mechanical properties of materials at the microscale. This advanced optical technique...

A convex lens that brings an incident bundle of rays to a focus to produce intense heat at the focus.

A forerunner of the modern camera, this instrument had a focusable lens that produced a sharp image on the enclosure opposite the aperture but had no photosensitive material to record it.

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...