Photonics Dictionary: F

In imaging technology, assigning color to black and white images to differentiate features or convey information. Also called colorizing.

Entirely analogous to color photography, but inclusive of light bands that do not appear in the visible spectrum.

A multiple-beam interferometer, usually consisting of two flat plates, with high reflective ability. The plates are set parallel to one another by spacers so that lightwaves may bounce back and forth...

A set of rays through a lens originating at a common point and contained in one plane.

A fiber-coupled LED (light-emitting diode) refers to an LED device that is optically coupled to an optical fiber for the purpose of efficient light transmission. In this configuration, the LED serves...

An X-Y electrically addressable series of arrays with individual electron emitters bombarding a phosphor-coated transparent plate. The phosphor is induced into luminescence, similar to traditional...

An aperture located at an image plane of an optical system that determines the size and shape of the image.

A type of interferometer noted for producing narrow multiple-beam interference fringes. As a result, when compared with the Twyman-Green, the Fizeau interferometer has fewer optical components, does...

A bench photometer that depends on the inability of the eye to distinguish color in brief flashes of light. Any difference in the intensity of reflected colored samples, presented to the observer in...

The photographic recording of a subject that exhibits luminescence only for an extremely short time (10-8 s) after the exciting source is removed. In the process, the subject may be illuminated by...

Fluorescent proteins are proteins that exhibit the property of fluorescence, which is the ability to absorb light at a specific wavelength and emit light at a longer wavelength. These proteins are...

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 fluorophore is a molecule or a portion of a molecule that has the ability to emit light upon excitation by an external energy source, such as ultraviolet or visible light. The process by which a...

A microscope that uses a flying spot scanner, directed through the eyepiece, as a light source to determine the features of a transparent specimen. The flying spot is modulated by the varying density...

A device used to scan, with a small, intensely bright spot, portions of a picture surface and to transform the original picture into a series of electrical signals. In optical character recognition,...

The focal length of a lens is the distance between the lens's optical center (or principal point) and the image sensor or film when the lens is focused at infinity. In simple terms, it is the...

The Foucault test is performed by moving a knife edge laterally into the image of a small point source. The eye, or a camera, is placed immediately behind the knife edge, and the exit pupil of the...

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.

The central portion of the retina that has the greatest sensitivity to form and color.

A type of internal photonic connection in an integrated circuit in which a holographic grating is used to focus light at points on a silicon chip, maximizing the speed of signal propagation.

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...

Two plane mirrors that are not wholly located in the same plane. When light from a point source or slit reflects from the two mirrors, interference bands are revealed in the region where the light...

A type of quarter-wave retarder in the form of a glass rhomb; light entering the retarder undergoes two total internal reflections, producing a change in phase.

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...

Molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid or tube. Also called buckyballs. Cylindrical fullerenes are called carbon nanotubes or buckytubes.