Photonics Dictionary

The physical center of the lens; it is on the axis of the lens, halfway between the front and rear vertex. It is sometimes referred to as the mechanical center of the lens.

The position and shape of the image of a point source, as predicted by geometric optics alone. The geometric image is to be differentiated from the diffraction image, which is determined from...

Metamerism that occurs when the geometry of illumination or viewing is changed.

In image processing, mathematical operations that change spatial geometry, as for instance scaling, translating, rotating or otherwise manipulating the perspective. Also called geometric manipulation.

A field of physics that deals with light as if it truly were composed of rays diverging in various directions from the source and abruptly bent by refraction or turned by reflection into paths...

A technique used to create an achromatic phase shift based on the principle of geometric phase. The phase shift is experienced by a light beam as a result of a cyclic change in its state of...

The area of optics in which the propagation of light is described by geometrical lines (or rays) governed by Fermat's Principle. Geometrical optics is useful as long as the objects in which the light...

The ratio of aperture area over receiving area for a specific lens. Also called geometric concentration.

In aerial photography, the geometric method of indicating the three-dimensional location of ground points from a pair of aerial photographs.

1. A geometrical arrangement of two or more light beams for use in laser shows, object detection or other applications requiring arrayed multiple beams. 2. A mathematical 2 X 2 or 3 X 3 matrix for...

A mode that is confined by virtue of a lower-index medium surrounding the cladding. Cladding modes, in the terminology of mode descriptors, are equivalent to cladding rays in the terminology of...

A coherent fiber bundle (CFB), also known as a coherent fiber optic bundle, is an assembly of multiple optical fibers arranged in a specific geometric pattern to maintain the spatial coherence of...

A solid with a structure that exhibits a basically symmetrical and geometrical arrangement. A crystal may already possess this structure, or it may acquire it through mechanical means. More than 50...

A regular, periodic, geometric array of points corresponding to the positions of the atoms in a perfect crystal.

The point on a cutting line that will become the geometrical center of the cut lens.

1. The grinding or edging of a lens so that the geometrical center and optical center do not coincide. 2. The shifting of an optical element from the system's optical axis, sometimes done on purpose...

Also called DLIP, a high-speed, high-resolution processing technique that uses high-power, pulsed laser systems to directly ablate micro- and nanoperiodic structures with different features on large...

An electron lens consisting of a homogeneous axial electric field and a magnetic field used in high-quality image tubes for high modulation transfer function and small geometrical distortion...

A product of the area of a light beam (normal to its direction of propagation) and the solid angle that the beam includes; flux per unit radiance or luminance. Alternative terms: geometric extent,...

A radiation source that, unlike the point source, can be resolved by the naked eye into a geometrical image.

A fiber optic preform is a cylindrical glass rod or tube used as the starting material for manufacturing optical fibers. It serves as the precursor from which optical fibers are drawn. The process of...

The allowable departure from the given figure or geometrical form. It may be described in terms of fringes or wavelengths.

In optics, the geometrical form of an optical surface.

The process in the manufacture of an optical system that gives it the required geometric shape.

Often referred to as the geometric center of a given image or image plane, the centroid of an image is a fixed point located at the intersection of all of the hyperplanes of symmetry within that...

The horizontal distance between the 90° meridian of a bifocal lens and the geometrical center of the segment.

A semiconductor device with the property of conducting current more easily in one direction than the other. It has two terminals containing a single crystal of semiconducting material that ranges...

A type of geometrical distortion that brings about a trapezoidal display of a nominally rectangular picture. Usually produced when a picture is projected abnormally to the screen.

In an optical waveguide, a ray for which geometric optics would predict total internal reflection at the core boundary, but which suffers loss by virtue of the curved core boundary.

In the spectral sense, an optical source that emits one or more spectrally narrow lines as opposed to a continuous spectrum. In the geometric sense, an optical source whose active (emitting) area...

The process or act of measuring the geometric properties of an object or image.

Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication, and utilization of artificial structures called metasurfaces to control and...

A device designed to measure linear or rotary motion by detection of the movement of markings on a transparent medium past a fixed point of light. The encoder has a moving code plate, a glass disc...

Mathematically defined as the product of etendue (or throughput) and the square of the refractive index, the optical extent is the quantitative value that describes the geometrical limit to how much...

In a medium of constant refractive index, the product of the geometrical distance and the refractive index.

Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter and its manifestation as both particle and wave phenomena. It encompasses the...

The term applied to the geometrical structure of radiometry or of the propagation of any quantity that is conversed and that travels in straight lines at velocities characteristic of the medium.

Photogrammetry is a technique used to obtain accurate three-dimensional measurements of objects and environments through the analysis of photographs or imagery. It involves extracting information...

Photolithography is a key process in the manufacturing of semiconductor devices, integrated circuits, and microelectromechanical systems (MEMS). It is a photomechanical process used to transfer...

The branch of science that treats light as a wave phenomenon wherein light propagation is studied by wavefronts rather than rays, as in geometric optics.