Photonics Dictionary: C

A lens, one surface being a cartesian oval, that produces an aplanatic condition.

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 high-quality, narrow-angle lens of high aperture designed for low magnification in the recording of cathode-ray tube images.

A lens system in which the centers of curvature of all surfaces fall on a common axis.

A convex or positive lens that serves to collect energy and direct it into subsequent system optics.

A lens made up of a number of lens elements arranged into two or more groups.

A lens composed of two or more separate elements of optical glass that may or may not be cemented together. The surfaces of the elements are shaped to reduce or eliminate the aberrations inherent in...

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

A lens having surfaces whose centers of curvature coincide.

A lens with a surface that is a cone instead of the usual sphere.

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

Any lens with at least two lens elements, each of which can be used singly or in combined configurations.

The simplest lens in which all primary aberrations may be corrected. It consists of two positive crown elements on either side of, and spaced away from, a negative flint element.

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 compound lens, the dimensions and materials of which have been so chosen that the lens is appreciably free of aberrations.

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

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 standard lens interface initially made for 16mm movie cameras and now used primarily on closed-circuit television cameras. It is a 1-in.-diameter, 32-thread-per-inch interface with a...

An optical material used in place of crown glass to produce lenses with extraordinary correction of chromatic aberrations. Its high coefficient of thermal expansion and its tendency to absorb...

A calcium indicator is a molecule that is sensitive to changes in calcium ion (Ca2+) concentrations in biological systems. These indicators are commonly used in various fields, including cell...

The production of visible light by infrared radiation whereby the light is produced by heat and not by any direct change in wavelength; the transformation is indirect.

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.

An apparatus, designed for use with a camera, that is used to rapidly open the path from lens to film, to maintain the opening throughout exposure and to close the opening in rapid succession. The...

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...

A resin obtained from the balsam fir, Abies balsamea, used as a lens cement.

A gas laser in which the energy-state transitions between vibrational and rotational states of CO2 molecules give emission at long IR, about 10 µm, wavelengths. The laser can maintain...

Focal, nodal or principal points of a lens. If the respective distances of the object and image are measured from the cardinal points, all thin-lens equations are applicable to thick lenses.

A system that uses both reflection and refraction to achieve its focal power. While the relative powers of the lenses and mirrors vary from system to system, the use of the reflective surfaces to...

Cathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the form of light, into an electrical signal. Photocathodes are components used in...

A fiber optic end plate constructed by drawing a bundle of parallel fibers embedded in glass and cutting it into thin slices. These slices are assembled in a plane and heated to produce a...

An optical system in which the only image-forming elements are curved-surface mirrors; e.g., a Cassegrain lens system.

A CCD camera, or charge-coupled device camera, is a type of digital camera that utilizes a CCD image sensor to capture and record images. CCD cameras are widely used in various applications,...

A CCD image sensor, or charge-coupled device image sensor, is a type of electronic device used to convert optical images into electronic signals. It is a key component in digital cameras, camcorders,...

1. A single unit in a device for changing radiant energy to electrical energy or for controlling current flow in a circuit. 2. A single unit in a device whose resistance varies with radiant energy....

The surface of an element of a compound lens that will produce the cemented interface. The curves of this interface are called inside curves. To facilitate cementing, the two inside curves should...

The center of the sphere of which the surface of a lens or mirror forms a portion. Each curved surface of a lens has a center of curvature; the surfaces may be convex or concave.

That viewpoint at which the angular subtenses of points in the picture are identical to angular subtenses of the original points in the scene, at the camera lens.

The lens thickness measured at the optical axis.

The surface curvature designed to reduce the marginal error found in the periphery of a spectacle lens.

1. Mounting a lens or mirror so that its optical axis is coincident with the optical or mechanical axes of other portions of the system. 2. The machining (edging) of the outside diameter of a lens...

In a perfectly centered lens, the mechanical axis (defined by the ground outside the diameter of the lens) is made to be exactly coincident with the optical axis (defined by a line through the...