Photonics Dictionary: C

A reflecting grating ruled on a concave spherical surface that not only disperses the light but focuses the spectrum. The great advantage of this grating lies in the fact that no separate collimating...

A lens with one concave surface and one convex surface; synonymous with meniscus.

A lens having surfaces whose centers of curvature coincide.

A partially filled or empty energy band through which electrons can move easily. The material can therefore carry an electric current. The term is usually applied to semiconductors.

A type of laser welding of thin materials using a defocused or low-power carbon dioxide laser beam. The energy is absorbed by the material through conduction and melts the material to produce an edge...

A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator configuration used in laser systems. The term confocal in this context refers to the...

A parabolic, elliptical, hyperbolic or circular section created when a solid cone is intersected by a plane.

The two points on the principal axis of a mirror or lens so positioned that light emitted from either point will be focused at the other, i.e., object and image points.

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 type of photoelectric proximity mode sensing incorporating a lens system to focus the light from the emitter in a small, concentrated spot at a specific point in front of the sensor. Also referred...

Also known as convergent lens or convex lens. A lens that converges an incident bundle of rays to a focus.

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...

An image-enhancement technique in which each pixel is subjected to a mathematical operation that groups it with its nearest neighbors and calculates its value accordingly.

A powerful and flexible machine-learning approach that can be used in machine vision to help solve difficult problems. Inspired by biological processes, multiple layers of neurons process portions of...

The coupled pairs of electrons that carry supercurrents through the body of a superconductor, relative to a coherent macroscopic wave function with the superconductor.

The combination of two or more different small-molecule monomers into a polymer.

An early type of nonvacuum photocell consisting of a layer of copper oxide on a metallic substrate, with a thin transparent layer of a conductor over the oxide. When light falls on the cell, a small...

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 mass-relieving method whereby material is removed through the sides of a reflector in a direction parallel to the surface. A method of cutting a cylindrical piece of material from a large piece.

A telescope in which a mask occults the solar disk, generating an artificial eclipse and allowing observation and recording of the sun's corona.

Solar regions characterized by low density and open magnetic fields where high-speed solar wind streams originate. Originally believed to be "M'' regions, coronal holes are the precursors of the...

Translucent collector developed to compensate for the partial blocking of a flat surface's collection angle that normally occurs in spectroradiometry. The device samples radiant flux according to the...

The ability of particular pure liquids to doubly refract when influenced by a magnetic field with a direction that is transverse to the light beam.

The quantity (C) of electricity transported in one second by a current of one ampere.

In microscopy, the chamber that is contained on a microscope slide to hold a certain amount of fluid. It is calibrated accurately to determine the number of cells and other elements while the...

A rangefinder on a camera that is integrated with the focusing mechanism so that when an object's range is determined, the camera is automatically in focus.

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...

Cresyl violet, also known as cresyl violet acetate or cresyl echt violet, is a synthetic organic compound belonging to the class of triarylmethane dyes. It is commonly used in histology and...

The least angle of incidence at which total internal reflection takes place. The angle of incidence in a denser medium, at an interface between the denser and less dense medium, at which the light is...

Calculation of the probability of an interaction between two types of particles, such as light absorption, excitation or energy transfers. The probability that one incident particle will interact as...

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...

1. A defect inherent in a multiple-axis positioning system whereby an adjustment of one axis causes an undesired change in another; its severity depends upon the degree to which the positioning axes...

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

A vacuum pump in which pressure is reduced by condensing gases on surfaces cryogenically cooled to about 20 K (liquid hydrogen) or 4 K (liquid helium).

The spectrographic analysis of matter that is in a cooled state. Generally, a mechanical refrigerator is used to lower the temperature of the sample, allowing isolation and study of the sample and...

An instrument that is used to detect high-energy particles by the pulse of the current formed when a particle passes through a normally insulating crystal to which a potential difference is applied.

The unusual and anisotropic diamagnetic quality observed in particular crystals such as those composed of bismuth.

The naturally occurring crystalline form of silicon dioxide. It is slightly birefringent and exhibits rotary dispersion of light rays transmitted along the crystal axis, both right-hand and left-hand...

The internal lens of the eye. It is semielastic to permit changes in its power when focusing on objects at near distances.

A small region within a single crystal where the molecules form a perfect lattice.

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...