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Excelitas Technologies Corp. - X-Cite Vitae HP 11/24

8,726 terms

Photonics Dictionary

FIFO

first in/first out

fifth-order aberrations

Secondary aberrations remaining after the primary (Seidel) aberrations have been corrected.

fig

figure

figure tolerance

The allowable departure from the given figure or geometrical form. It may be described in terms of fringes or wavelengths.

figure

In optics, the geometrical form of an optical surface.

figuring

The process whereby the shape of an optical surface is altered by polishing.

filament emission

The freeing of electrons from a filament in an electron tube as the result of the filament being heated by an electric current.

filament transformer

A transformer that is designed to regulate the amount of current that passes through an electron tube's filament.

filar eyepiece

A measuring eyepiece with a screw-micrometer-driven crosshair used to measure the size of the image.

fill factor

In solar energy technology, the percent of usable land covered by collectors. The horizontal collector is the only design that exhibits 100 percent fill factor.

fill ratio

The ratio of active to inactive areas on a pixel.

film plane

The site behind the lens system in a camera where photographic media are positioned for exposure.

film platen

A mechanism in a camera designed to position the film in the focal plane for exposure.

film reader

A device used to scan images or information on photographic film for the subsequent relay of information.

film recorder

An instrument designed to place nongraphic information, usually generated by a computer, onto photographic film. The information is generally encoded as a series of opaque and translucent spots, or...

film scanning

The process by which the light from the images of photographic film is encoded into electrical signals for video transmission.

film thickness gauge

An interferometer spectrometer designed to measure thicknesses of thin films or layers by recording the interferogram and by having a computer within the instrument to establish the distance between...

film weld

The butt (edge to edge) splice of two pieces of film produced by a heat splicer that melts the edges together; used in editing motion picture film.

filovirus

Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and non-human primates. The name "filovirus" is derived from their filamentous...

filter

1. With respect to radiation, a device used to attenuate particular wavelengths or frequencies while passing others with relatively no change. 2. See digital filter.

filter factor

The necessary increase of a photograph's exposure time as the result of the additional absorption of light by the filter being used.

filter grating

A grating used as a reflectance filter, particularly in the far-infrared. Small plane gratings, blazed for the wavelength of the unwanted radiation, are produced for this purpose.

filter kernal

A function used in a convolution filtering operation. The image to be filtered is convolved with the filtering kernel to obtain the enhanced image.

filter spectrophotometer

A spectrophotometer that makes use of filters to isolate narrow bands of the spectrum.

filter wheel

A device that holds a number of filters and allows the filter with the desired characteristics to be rotated into an optical aperture.

finderscope

A low-power telescope with a wide field of view, typically attached to a higher power telescope with a narrower field of view. This enables an observer to locate a celestial object with the...

finesse

For a Fabry-Perot interferometer or etalon, a value for the transmission bandwidth which can be calculated as the ratio of the free spectral range to the full width half maximum of the transmission...

fingerprint camera

A fixed-focus camera designed to record the ink impression of fingerprints that have been impressed on a card or form for record purposes.

fining

A grinding process that employs fine emery.

finished lens molding

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

finite sampling theorem

A finite version of Shannon's sampling theorem that states that a class of functions can be reconstructed exactly by a sufficient number of spectral samples; the reconstructed function is an explicit...

FIR

full indicator reading; far-infrared

fire cracks

Small clefts or fissures that penetrate the glass surface in the form of short-hooked crescents. Fire cracks result from a sudden excessive change in temperature.

first principal point

The principal point of a lens relative to the object space.

first window

The spectral transmission window in silica-based fibers between 830 and 850 nm.

first-order optics -> Gaussian optics

1. That branch of optics that illustrates the theory in which q is substituted for sin q in Snell's law. Effective results are achieved if the aperture and field angle are made very small. The...

first-order spectrum

The separate spectral lines formed by a diffraction grating that are characterized by one wavelength difference in path length between adjacent slits.

first-order theory -> Gaussian optics

1. That branch of optics that illustrates the theory in which q is substituted for sin q in Snell's law. Effective results are achieved if the aperture and field angle are made very small. The...

first-side meniscus

The process of grinding the concave surface of a single-vision spherical lens.

first-side toric

The process of grinding the toric surface of a single vision sphero-cylindrical lens.

first-surface mirror -> front-surface mirror

An optical reflector with the reflective coating applied to the front surface of the substrate. This eliminates the ghost image formed with second-surface mirrors.

FIRT

far-infrared transmission

FIS

fluoro-immunosensor

FISH

fluorescence in situ hybridization

fish-eye lens

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...

FIT

fast ion transport; flexible infrared transmission

FITL

fiber in the loop

fixed axis of rotation

The locus of points in a system along a line that remains stationary while the remainder of the system rotates.

fixed focus

Describes devices that are not provided with a means of focusing.

fixed-focus mode -> convergent beam sensing mode

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...

Photonics Dictionary

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