Photonics Dictionary

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 lens made up of a dielectric material that is capable of influencing radio waves much in the same way an optical lens influences light.

A lens with aberrations corrected to the point that residual wavefront errors are substantially less than one-quarter the wavelength of the energy being acted upon.

Any optical device that utilizes diffraction in an image-forming capability. Familiar diffractive lenses are zone plates, holographic lenses, kinoform lenses and binary optics.

A lens with one surface convex and the other concave, the latter having the greater curvature. It also is known as a diverging meniscus lens.

A diverging lens is a type of lens that causes parallel rays of light to spread out or diverge. It is thinner in the center than at the edges and is commonly referred to as a concave lens. The most...

A general-purpose lens, also known as the Celor lens, used widely in photography and commercial processing; it has the form of a triplet with a split flint element.

A diverging lens with both surfaces concave.

A converging lens with both surfaces convex.

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

See periscopic lens; rapid rectilinear lens.

An optical system having two sets of components separated by an air space, while successive lenses in each set are cemented together.

A device that uses four electrodes set in an alternating positive-negative polarity series to focus the beams of charged particles employed in electron microscopes and particle accelerators.

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...

An electrostatic device that uses an electric potential barrier to allow the transmittance of electrons at or above a set level of energy while stopping the passage of those below it.

An electric field produced to influence an electron stream much in the same manner that a lens affects a light beam.

The electrical distribution that serves to influence an electron beam in the same way that an optical lens affects a light beam.

The lens of an eyepiece nearest the observer's eye.

A family of lenses commonly used in scan systems for reading or printing documents. The lens must be designed such that the image height is proportional to the scan angle (Theta), not the tangent of...

A method of terminating optical fibers by forming a lens directly on the end of the fiber, eliminating the need for precise end-to-end placement or epoxy sealing in fiber connections.

1. A lens situated at or near the plane of an internal image to project the aperture of a previous objective or erector upon the aperture of a following lens. 2. A lens at or near the plane of a...

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

A type of wide-angle lens that has an angular field above 140° and that exhibits barrel distortion. The most commonly used fish-eye lenses have a field of about 180°, though they are...

A lens that focuses on a flat plane because its field of curvature is close to zero.

A lens having an extremely high aperture and used in the recording of x-ray fluorescent screen images. It often is specially designed for the camera, the color of the light and the image...

A Fresnel lens is a type of optical lens that consists of a series of concentric grooves or steps carved into a flat, thin piece of transparent material, typically plastic or glass. This design...

A telescope objective with excellent spherochromatic correction, consisting of a meniscus crown and a meniscus flint, both convex to the long conjugate.

The effect of a powerful gravitational field on light traveling through the field. This effect is detectable in astronomical observations when light from a distant source passes a massive object...

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...

A fish-eye lens designed to photograph cloud formations over the entire visible sky.

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

A series of permanent holograms in dichromated gelatin formed by opening total page-composer apertures and setting a point source of light in each storage location. It performs much like a...

An infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating infrared (IR) radiation within the infrared spectrum. These lenses are used in...

A lens that has a mount, usually bayonet or screw type in design, that can be used on a camera in place of lenses with the same mounting. This allows one camera body to be used with lenses of...

A lens that is implanted within the eye to replace the eye lens, which has been removed because of cataract or other defect.

A dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is focused on the lens surface at a point diametrically opposite the...

A machine vision lens is a specialized optical lens designed for use in machine vision systems, which are used for automated inspection, measurement, and quality control in industrial applications....

A camera lens, used in macrophotography, that is designed and corrected to produce optimum definition of a nearby object when it is photographed at a magnification of approximately1:1.

An arranged series of coils, magnets or electromagnets disposed in such a way that the resulting magnetic fields generate a Lorentz force that is used to then focus or deflect beams of rapidly moving...

A lens that has one convex surface and the other concave.

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...

A microlens array is a grid-like structure composed of numerous small lenses, typically arranged in a regular pattern. Each individual lens in the array is referred to as a microlens. These...