Photonics Dictionary

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...

A spheric lens, also known as a spherical lens, is a type of optical lens with at least one surface that is part of a sphere. This means that the lens surface is curved in a symmetrical manner,...

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...

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...

Also known as aplanatic lens. A lens corrected for spherical aberration and coma.

A system that satisfies the Abbe sine condition, and is free from spherical aberration and coma.

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...

Not spherical; an optical element having one or more surfaces that are not spherical. The spherical surface of a lens may be slightly altered so as to reduce spherical aberration. Aspheric surfaces...

An optical system having one or more lens or mirror components that have nonspherical surfaces. These surfaces, whether reflecting or refracting, serve to advance or retard the incident wavefront,...

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...

Any irregular motion, variation in intensity or change in color that arises because of atmospheric turbulence during the observation of an astronomical phenomenon or object.

Irregularities and disturbances in the atmosphere that are of particular interest because they induce random temporal and spatial phase and amplitude fluctuations that destroy the optical quality and...

A range of wavelengths within which radiation transmitted through the atmosphere suffers relatively little absorption by atmospheric gases.

Attenuation refers to the gradual loss or reduction of intensity, force, or magnitude of a particular property as it propagates through a medium or travels over a distance. This concept is prevalent...

In gradient index optics, a gradient profile in which the refractive index varies along the direction of light propagation, or optical axis. Axial gradient lenses can be used to correct spherical...

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 semispherical or conical lens created directly on the core of an optical fiber to focus light from a laser into the fiber core.

A cylindrical lens is an optical component that has different curvatures along its two orthogonal axes, resulting in a shape resembling a cylinder. Unlike spherical lenses, which have the same...

A telescope that corrects dispersion and spherical aberration through the use of one or more lenses, usually smaller than the objective lens, that are positioned at a distance from the objective lens.

A fast, wide-angle lens used in television and photographic cameras, with excellent overall correction, but subject to residual oblique spherical aberration.

A method used to produce precision spherical and aspheric molded glass lenses without grinding or polishing.

The process of grinding the concave surface of a single-vision spherical lens.

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...

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...

A calculated function that can be achieved experimentally with interferometric analysis of complex atmospheric altitude; expressed as a relation to the turbulence integrated over the entire...

The term gradient-index profile refers to a specific type of refractive index distribution within an optical material. In optics, the refractive index of a material describes how much the speed of...

A GRIN (gradient index) lens is a type of optical lens that utilizes a gradient in refractive index across its volume rather than having a uniform refractive index like conventional lenses. This...

Machinery used to grind and finish a component, such as a lens or prism, to a desired precision. Usually such machines carry a cup-shaped or flat tool (lap) into close contact with the part. An...

A test for spherical aberration, coma or astigmatism in which incident rays from a point source are isolated by small holes in a metal disc located close to the lens or mirror under test....

A photographic recording of interference patterns between a plane wave and a spherical wave on a high-resolution photographic emulsion.

A measure of the closeness with which an optical image is capable of resembling the original object. The factors that affect image quality are lens aberrations, diffraction, dirt and stray light...

An interferometer that functions by first detecting the light striking each aperture and then combining the two detector outputs. With an intensity interferometer, the primary collectors need not be...

An atmospheric nonlinear process unique to CO2 laser wavelengths, whereby CO2 absorbs 10.6-µm radiation and the CO2 molecules in the (100) vibrational state are excited to the (001) level, and...

A metal tool used to grind lenses with loose abrasive (see diamond cutting tool). The functional surface of the lap is carefully formed to be opposite the curve to be produced on the glass (concave...

Laser-induced fluorescence (LIF) is a spectroscopic technique that involves using a laser to excite molecules or atoms, leading to their emission of fluorescence light. This technique is widely used...

The method that, by measuring the absorption along an atmospheric path at wavelengths ranging from two to a continuum, can determine pollution concentrations of gases.

Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main categories based on wavelength: near-infrared (NIR), mid-wave infrared...

Magnetorheological finishing (MRF) is a precision optics polishing technique used for shaping and finishing optical surfaces to achieve extremely high levels of smoothness and accuracy. It is...

A thick meniscus lens arranged concentric with the center of curvature of a spherical mirror to produce an image free of spherical aberration.

A catadioptric lens assembly consisting of a Maksutov corrector and a spherical primary mirror.

A double-surfaced catadioptric spherical mirror whose spherical first surface consists of a negative meniscus (concave) lens and second rear surface is a spherical mirror. This combination utilizes...

An anastigmatic lens with a thick meniscus construction that flattens the field and corrects chromatic and spherical aberration.

A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light at a subwavelength scale. Unlike traditional lenses made of glass or other...

MWIR stands for mid-wave infrared, referring to a specific range of wavelengths within the infrared spectrum. Infrared radiation is categorized into three main regions based on wavelength:...

Mie scattering, named after the German physicist Gustav Mie, refers to the scattering of electromagnetic radiation (such as light) by spherical particles. Unlike Rayleigh scattering, which is...

A form of shearing interferometer that contains a simple wedged (plane-parallel) glass plate with a nonzero optical path difference to create interference between split optical wavefronts. The...

A lens used in the optical testing of an aspheric surface. It converts a spherical wavefront into one that precisely matches the surface under test. When the wavefront is reflected from that surface,...