Photonics Dictionary

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

Floquet-Bloch oscillations refer to a phenomenon in condensed matter physics, specifically in the context of periodic potential systems subjected to an oscillating external field or periodic...

A fiber optic device that uses a HeNe laser, beamsplitter, monochromator and photomultiplier to detect trace levels of chemicals and viruses in samples inside or outside the body.

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 form of image intensifier designed to amplify a weak fluoroscopic image. The image is received at an input phosphor screen, as opposed to the light-sensitive electrode emitter used in regular image...

Flux per unit area measured normal to the direction of propagation of the flux.

The application of ultraviolet, x-ray, infrared and conventional photography to law enforcement.

Förster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced fluorescent molecules. This phenomenon is named after the German scientist...

A hologram formed by the recording of a plane object situated in the focal plane of a lens so that each object gives rise to a parallel beam of light incident on the plate. A collimated reference...

An instrument using a Michelson interferometer, a beamsplitter, two plane mirrors and a detector to give Fourier analysis of the detector signal to provide the desired spectrum.

Any of the various methods of decomposing a signal into a set of coefficients of orthogonal waveforms (trigonometric functions).

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 piece of uniform birefringent material placed at a 45° angle to the plane of polarization in a polarizing microscope to indicate changes in color caused by interference when a birefringent...

A gas laser wherein the gas mixture is not exhausted into the atmosphere but is continually recycled. It is excited in the active region, cooled and re-excited. The GTL requires no constant gas...

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

A photometer used to measure sky brightness and polarization associated with zodiacal light, background starlight, F-region airglow and spacecraft corona.

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

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...

An optical device that permits the alignment of a gun, cannon or rocket launcher system with its target.

A filter that allows heat radiation from an incident beam to pass without absorption or reflection.

The capability of the spatial distributions of incident and reflected flux to interchange completely without alteration of the measured reflectance.

Extensive data storage in the form of bits, with the use of high-resolution photographic materials and optics, and generally a laser.

A satellite-borne remote sensing device capable of transmitting images at 10 and 20 m resolution from an altitude of 830 km, each sensor covering a ground area of 60 km, by means of a folded...

A high-sensitivity camera is a type of camera designed to perform well in low light conditions, capturing clear and detailed images with minimal noise. These cameras typically feature advanced sensor...

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 analysis used for problems of wave propagation. The principle notes that each point of an advancing wavefront is the center of a new disturbance, the source of a new series of waves. It also notes...

A hypercentric lens refers to a lens system where the chief rays of light from an object are directed through the center of the lens aperture, ensuring that the entrance pupil is situated at...

With respect to photography, the process used to increase the effective speed of an emulsion between manufacture and exposure.

An image intensifier, also known as an image intensification tube or image intensification device, is a specialized electronic device used to amplify low-light-level images to make them visible to...

The active control of various aspects (optical element position, airspace thickness, etc.) of an optical system that compensates for unwanted movement of the image that is caused by mechanical and...

Any arrangement of a bundle of optical fibers that alters the shape of the image. For example, by systematic regulation of the spacing of the fibers from the entrance end to the exit end, a...

The processing of an image or portion of an image by transform coding and analysis. Fourier, Hadamand, Kronecker and Eigenvector transforms are applicable to image transformation.

An energy transition concerned with the combination of a photon and a phonon.

Any of the photoelectric and thermal detectors, spectrographs and monochromators, thermographs, scanners, amplifier tubes, snooperscopes and related equipment developed for use with infrared...

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...

Inline inspection involves performing quality checks, measurements, or tests on products or materials while they are being produced or processed, rather than inspecting them separately in a dedicated...

The total optical power loss caused by the insertion of an optical component such as a connector, splice or coupler into a fiber optic system. See attenuation.

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

A method that produces low-loss optical fibers. A glass tube rotates while reactants pass through the tube and heat is externally applied by a burner that traverses the tube. The oxidizable vapors in...

A small round mirror on the end of a handle used for viewing inside an inaccessible cavity.

Instantaneous field of view (iFOV) is a term commonly used in the context of remote sensing, imaging systems, and optical instruments. It refers to the specific portion of a scene that an optical...

The tendency to adjust an instrument such as a microscope so that the viewed image appears much closer than infinity.

With respect to color photography, the measurement of the way the color film modulates the radiant flux in the optical system containing the film.