Photonics Dictionary: C

Method of disk rotation used for optical disk drives, in which the spindle motor decreases the speed of the disk's rotation as the head moves from the inner tracks to the outer, so that the radial...

Reciprocal of the dispersive power of an optical material. See Abbe constant.

Also called color blocking. The formation of a block by making optical contact between a number of optical elements and a large optical flat.

The radiography of small objects having detail too fine to be seen by the unaided eye. The resulting negative, when optically enlarged, can be examined.

In optical character recognition systems, the identification of a character facilitated by means of known factors governing its appearance in a particular context; e.g., the first character in the...

A method in optical character recognition in which a mobile light beam scans the outlines of characters for subsequent reading of these outlines.

1. In optics, the bending of light rays toward each other, as by a convex or positive lens. 2. Turning in the eyes to view a near object. 3. In a television picture tube, the crossing of the...

The curved boundary between two optical media of different refractive indices, which causes convergence.

Convex is an adjective used to describe a surface or shape that curves outward, bulges, or has a rounded and outwardly extending appearance. In the context of geometry or optics, a convex shape is...

A camera mounted on an optical bench with an easel to hold the material to be copied. Magnification can be varied over a wide range by sliding the camera and easel.

A threadlike inclusion within a blank of optical glass. Rarely found in quality optical materials.

The light-conducting portion of an optical fiber, defined by the region of high refractive index.

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 corner cube, also known as a corner reflector or retroreflector prism, is a type of optical device used to reflect light or electromagnetic waves back towards their source with minimal deviation in...

In rangefinders and height finders, a rotatable or sliding wedge-shaped element used to divert the line of sight precisely to correct errors in the optical system.

An optical wedge of very small angles that admits light while sealing out moisture and dirt and that may be rotated to compensate for the errors in the entire system. Correction windows are sometimes...

An optical element designed to correct each zone of a reflector or refractor for spherical aberration.

1. In color development, the chemical that combines with certain by-products of the development procedure to form a dye. 2. Device for distributing optical power among two or more ports. 3. Device...

The fraction of available output from a radiant source that is coupled and transmitted by an optical fiber.

A technique used in integrated optics where a groove is cut on a substrate surface and covered by a thin film to facilitate the construction of filters, resonators, beamsplitters and grating couplers...

In an optical system, the aperture size at which the lens gives its best overall performance.

Fine lines, wires or threads used in the focal plane of many optical instruments to point out and locate particular objects in the field of view. They were formerly made from a single strand of...

The measurable leakage of optical energy from one optical conductor to another. Also known as optical coupling.

One of the two principal types of optical glass, the other being flint glass. Crown glass is harder than flint glass, and has a lower index of refraction and lower dispersion. Both types are used in...

The physical limit of an optical fiber or cable to withstand an applied force or weight perpendicular to the axis of the fiber.

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...

The use of chemicals or radiation to induce a desired change in a substance; e.g., some optical adhesives are set by exposure to ultraviolet light and are said to be UV-curing.

1. In detector technology, the long wavelength at which detector response falls to a set percentage (usually 20 or 50 percent). 2. In fiber optics, the shortest wavelength at which a fiber transmits...

Adhering material used to glue optical components that transmit in the infrared. It is easily dissolved by acetone.

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 form of monochromator optical system consisting of two spherical concave mirrors used in conjunction with a movable diffraction grating.