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Teledyne DALSA - Line Scan Leader 5/24 LB
FOC Dictionary Terms

hyperfocal distance
That object distance at which a camera must be focused so that the far depth of field just extends to infinity. The near...
stimulated thermal scattering
Light from a pulsed laser focused into nonsaturable absorbing fluid that generates a strongly backscattered light beam with...
laser spark
Breakdown of a gas produced by the attenuation of an intense pulse of focused laser light.
astigmatic spectral line
In an astigmatic grating, the image of the entrance slit located at the primary focus.
power
With respect to a lens, the reciprocal of its focal length. The term power, as applied to a telescope or microscope, often...
proximity-focused image tube
A planar photocathode and a planar phosphor screen mounted in a close-spaced parallel configuration in an evacuated...
photon tunneling microscope
An instrument in which visible light beyond the critical angle from a metallurgical microscope is focused on a reference...
Ramsden eyepiece
An eyepiece consisting of two planoconvex lenses of the same focal length, with facing convex surfaces.
supplementary lens
A meniscus that is often fitted before a camera lens to permit focusing on near objects.
optically compensating zoom system
A variable focal length lens system that retains the object in focus as one or more lenses move as a unit along its optical...
light-emitting diode
An LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs...
focusing anode
One of the electrodes used to focus the electron beam of a cathode-ray tube. As the electrode's voltage is changed, its...
spectroscopy
Spectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves...
time of flight
(TOF) The length of time needed for a signal to arrive at and be reflected from the target. The basis of an active...
solid-state laser
A solid-state laser is a type of laser that uses a solid gain medium (as opposed to a liquid or gas) to produce coherent...
front focal length
scientific complementary metal-oxide semiconductor
Scientific complementary metal-oxide semiconductor (sCMOS) refers to a type of image sensor technology specifically designed...
f number (f/#)
The expression denoting the ratio of the equivalent focal length of a lens to the diameter of its entrance pupil.
focal plane assembly
An infrared imaging device composed of a detector array and readout electronics. It may include a cryogenic cooling system....
filovirus
Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and...
telephotometer
An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small...
variable-focus condenser
An Abbe condenser in which the upper lens element is fixed. The lower lens may focus the illumination between the elements...
depth of field
The distance, on either side of the object plane focused on, through which satisfactory image definition can be obtained....
dark-field condenser
A condenser that forms a hollow cone-shaped beam of light with its focal point in the plane of the specimen. If it is used...
bifocal lens
A two-part lens that has a different focal length for each part. Generally, it is used in eyeglasses to correct for both...
exciter lamp
A small incandescent lamp whose intense beam is focused on the optical soundtrack of a motion picture film. The soundtrack...
homocentric
A term applied to rays that possess the same focal point, which may be infinity, thereby meaning that the rays are parallel.
flange focal distance
The distance between the locating surface of the lens mount and the image plane.
ocular accommodation reflex
The eye's involuntary reaction in the process of accommodation. This reflex is most dramatic in response to looking at a...
ultramicroscope
A dark-field microscope used to view extremely small objects. These objects are suspended in a gas or liquid in an enclosure...
kron camera
Astronomical detector consisting of a photocathode isolated from the target by a coin value from which electrons are focused...
focometer
A device used to measure the focal length of an optical system or lens.
infrared optic
Infrared optics refer to optical components and systems designed to manipulate and control infrared (IR) light, which lies...
optical glass
Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems,...
autocollimator
An autocollimator is an optical instrument used for measuring small angular deviations with high precision. It operates on...
inner focusing
In a camera, the movement of one or more lenses behind the front lens, rather than of the front lens itself, to bring the...
multianode microchannel array detector
A photon-counting instrument for use in both space-borne and ground-based photometric and spectroscopic instrumentation....
burning glass
A convex lens that brings an incident bundle of rays to a focus to produce intense heat at the focus.
instantaneous field of view
Instantaneous field of view (iFOV) is a term commonly used in the context of remote sensing, imaging systems, and optical...
measuring eyepiece
Also known as an eyepiece micrometer. A microscope eyepiece that has a finely divided scale ruled or photographed on a...
microspectroscope
A system composed of a prism spectroscope and compound microscope to provide the visual comparison of two spectra...
diopter scale
A scale located on the eyepiece focusing screw and used to measure the amount of defocusing of the eyepiece in diopters. The...
lens disc
A rotating disc that holds several lenses of differing focal length about a diameter. Used to switch lenses in a system...
Huygenian eyepiece
An ocular having two planoconvex lenses that are formed from similar glass and that are separated by a space equal to half...
nanoparticle photonic resonator absorption microscopy
Nanoparticle photonic resonator absorption microscopy is a microscopy technique that combines the principles of photonic...
Nd:YAG laser
Nd:YAG laser refers to a solid-state laser that utilizes neodymium-doped yttrium aluminum garnet (Nd:Y3Al5O12) as the gain...
fixed focus
Describes devices that are not provided with a means of focusing.
SELFOC lens
Luneburg lens
A dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is...
disc
A piece of glass that eventually becomes the bifocal segment as it appears prior to being fused to the blank.
plasmonics
Plasmonics is a field of science and technology that focuses on the interaction between electromagnetic radiation and free...
multi-axis alignment
Multi-axis alignment refers to the process of aligning or adjusting components or systems in multiple spatial dimensions or...
lens
A lens is a transparent optical device that focuses or diverges light, allowing it to pass through and form an image. Lenses...
microprobe
An instrument that produces an intense, tightly focused beam of ions to stimulate emissions from a minute section of a...
focal power
In a symmetrical optical system this is a measure of the influence of the system upon the focus of a pencil of rays passing...
conjugate focus
light filament
Phenomenon caused by an ultrashort and ultra-intense light pulse propagating in a Kerr medium, such as air or water. When...
reflecting telescope
A telescope that uses a reflecting objective to focus an image of a distant object at a focal point.
two-photon excited fluorescence
Two-photon excited fluorescence (TPEF) is a nonlinear optical method that allows imaging of biological cells and living...
millidiopter
A unit of metric measure equivalent to 1 thousandth (or 10-3 ) of the standard unit of optical power which is the diopter (1...
iconometer
An instrument in which an object's image, produced by a lens of known focal length, is used to determine the object's...
actinic focus
That point in the electromagnetic spectrum at which an optical system focuses the most chemically effective rays.
focal point
That point on the optical axis of a lens, to which an incident bundle of parallel light rays will converge.
aperture mask
Also known as a shadow mask, a perforated plate placed between the focusing and accelerating electrodes, and the tricolor...
spatial filter
1. Generally, an emulsion mask having a clean annular region in an otherwise opaque region. It is designed to eliminate...
fiber-based confocal luminescence microscope
A microscope in which laser light is delivered through single-mode fibers that replace the pinhole usually used in confocal...
photon jet
A photon jet is a narrow, highly collimated beam of light that is formed when light interacts with small dielectric...
thin lens relationships
Formulas designating the relationships between image distance, object distance, focal length, refractive index, etc., of a...
front operating aperture
The restricting aperture located at the front of the lens. It is usually defined as the maximum diameter of the entrance...
laser confocal microscope
Rayleigh range
In the region of a Gaussian beam focus by a diffraction-limited lens, it is the axial distance from the point of minimum...
micro-optics
Micro-optics refers to the design, fabrication, and application of optical components and systems at a microscale level....
equivalent focal length
 scanning electron microscopy
Scanning electron microscopy (SEM) is an advanced imaging technique used in microscopy to obtain high-resolution,...
pincushion distortion
An aberration of a lens system caused by an increase in lens focal length as the field angle increases. The amount of...
laser texturing
Laser texturing is a manufacturing process that involves using a laser beam to selectively modify the surface of a material,...
negative-refraction metamaterial
An artificial material, engineered to have a negative refractive index value, such that light or any other form of...
retroreflecting multipass cell
Two lenses, separated by a distance equal to the sum of their focal lengths, and retroreflecting mirror assemblies, one of...
photocoagulator
An optical medical instrument that uses an intense, precisely focused beam of light to stop weakened blood vessels from...
plane grating
A transmission or reflecting grating with a flat or plane surface requiring a lens or concave mirror to focus the spectrum.
multifocal lens
A lens with internally adjustable elements to produce a range of focal lengths. Unlike a true zoom lens, a multifocal lens...
camera
A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material...
pointer eyepiece
A Huygenian eyepiece containing a pointer at its focal plane that is used -- when viewing an object through the eyepiece --...
fingerprint camera
A fixed-focus camera designed to record the ink impression of fingerprints that have been impressed on a card or form for...
aplanatic points
Aplanatic points refer to specific points in an optical system where certain aberrations, such as spherical aberration or...
plasma accelerator
A plasma accelerator is a type of particle accelerator that uses electric fields and magnetic fields to accelerate charged...
Fourier transform hologram
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...
lensometer
An ophthalmic instrument used to measure the magnitude and direction of the maximum and minimum powers of a spectacle lens,...
topology
Topology is a branch of mathematics that focuses on the properties of space that are preserved under continuous...
autocollimating spectrograph
A spectrograph in which the refracted beam returns almost along the path traveled by the incident beam, and is brought to a...
soft-focus filter
A filter that creates spherical aberration resulting in an image with a soft outline.
ionic focusing
Also known as gas focusing. The introduction of an inert gas into a cathode-ray tube for the concentration of the electron...
hyperopia
A vision defect commonly referred to as farsightedness. Results when the image of a distant object is focused beyond the...
reticle
A reticle, also known as a reticule or graticule, is a pattern or set of markings placed in the focal plane of an optical...
optics
Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter...
phase matching
Phase matching is a crucial concept in the field of optics, particularly in nonlinear optics and the generation of coherent...
diverging 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...
tracking
1. The process of following an object's movement; accomplished by focusing a radar beam on the reticle of an optical system...
beam shaper
A beam shaper is an optical device or system designed to modify the spatial profile or intensity distribution of a laser or...
axial color
A lens aberration that causes axial light rays having different wavelengths to focus at various points along the axis.
GRIN lens
A GRIN (gradient index) lens is a type of optical lens that utilizes a gradient in refractive index across its volume rather...
electromagnetic image tube
An image intensifier tube that uses a magnetic field for focusing. It yields high-quality images, but its use is limited by...
image jump
In optics, the term image jump refers to a displacement or shift in the apparent position of an image when a change occurs...
deflection focusing
The progressive defocusing of a cathode-ray tube display image that occurs when the deflected electron beam impinges on the...
phototheodolite
A camera equipped with angular scales in altitude and azimuth. The scale readings are imprinted on the film when an exposure...
segment height
In a bifocal spectacle lens, the vertical measurement of distance from the uppermost borderline of the bifocal segment to...
lensless microscopy
Lensless microscopy, also known as computational or holographic microscopy, is an imaging technique that captures and...
variable-focus lens
A lens assembly containing several movable elements to permit changing of the effective focal length (EFL). Unlike a zoom...
confocal resonator
A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator...
confocal spherical interferometer
An interferometer formed by two similar concave spherical mirrors arranged with the center of one sphere on the other...
Ross lens
A corrective lens system that is placed near the focal plane of a Newtonian telescope to increase its effective field of...
solar laser
A laser pumped by solar radiation focused by mirrors.
circle of least confusion
Best point of focus for an image in a beam of light at the smallest cross section of the beam.
focused laser scattering
A single-particle scattering technique in which an incident laser beam is tightly focused by means of lenses to yield a...
depth of focus
The range of image distances that corresponds to the range of object distances covered by the depth of field.
focusing scale
A scale on an optical instrument that indicates the condition of focus. May indicate the distance to the object or diopter...
electric quadrupole lens
A device that uses four electrodes set in an alternating positive-negative polarity series to focus the beams of charged...
zoom lens
An optical system of variable focal length, the focal plane remaining in a fixed position. This result is achieved by moving...
focus control
1. A mechanism that permits the focusing of an optical system.2. A means of obtaining the sharpest image from a cathode-ray...
electron-beam lithography system
An electron-beam lithography (EBL) system is a sophisticated nanofabrication tool used in the semiconductor industry and...
fixed-focus mode
 electrostatic focus
The use of an applied electrical field to focus a cathode-ray tube's electron beam.
intravital microscopy
Intravital microscopy is an imaging technique used to visualize biological processes within living organisms, typically in...
reflection x-ray microscopy
A means of high resolution study through the application of soft and hard x-rays onto a sample surface in order to obtain...
simple magnifier
A short focal length (less than five inches) positive lens used to produce a magnified image of the object being viewed....
Judas optics
A small defocused Galilean telescope mounted in a hole in a door. Viewed from inside through the positive lens, a wide-angle...
direct screen focusing
In a camera, the focusing of an image on the screen located at the camera's film plane. Once the image is in complete focus,...
Becke line
A band of light that appears along the outer edge of a transparent material under microscopic investigation and that moves...
electron-gun system
An electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find...
motion controller
In optics, a motion controller refers to a device or system that precisely controls the movement of optical components, such...
short-focus lens
 magnetically focused image tube
A vacuum tube in which a magnetic field is superimposed onto the tube's electrical field. When the two fields are aligned,...
Keplerian astronomical telescope
A simple form of astronomical telescope that uses a fixed objective and a focusable eyepiece. The objective forms an...
near point of eye
The closest distance to which the eye can focus on an object, normally taken to be 250 mm. The near point varies with age.
magneto-optic readout device
A device using the Kerr effect to read back the signals from mechanically recorded tapes and discs. It consists of a light...
nodal bench
A bench with instrumentation including a collimator, a microscope, positioners and a nodal slide used to rotate a lens about...
radiation pyrometer
Also known as radiation thermometer. A pyrometer in which the radiant intensity from the source to be measured is used to...
secondary color
An aberration that remains after primary color is corrected. Primary color causes the back focus of a lens to vary with...
off-axis paraboloid and ellipsoid mirror
Off-axis paraboloid and ellipsoid mirrors are specialized optical components used in various optical systems, particularly...
laser output
The laser output refers to the generated and emitted light produced by a laser system. This output is characterized by...
intensified charge-coupled device
A CCD image sensor that uses a proximity-focused image intensifier to provide greater sensitivity at low light levels.
concave
Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In...
laser annealing
Laser annealing is a process that involves using a laser beam to heat and modify the microstructure of a material, typically...
permanent magnetic focusing
The focusing of an electron beam by a magnetic field that permanently retains the majority of its magnetic properties.
lenticular color photography
A type of additive color photography using a lenticular structure impressed on a film base and a camera lens with a filter...
curvilinear distortion
A lens aberration in which the focal length varies radially outward from the center of the field. It has the effect of...
laser peening
Laser peening is a surface enhancement technique used to improve the mechanical properties of materials, particularly...
hero experiments
Laboratory experiments that focus on demonstrating new capabilities of a certain technology or device, usually without...
electrostatic image dissector
A nonmagnetic instrument utilizing an electrofocus and deflection tube with a photocathode for imaging purposes. The optical...
telescope lens
A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is...
binocular magnifier
A device having a pair of decentered lenses, one for each eye, that focuses on a single object as a magnifier. It is often...
hybrid focal plane array
A device where each pixel in the detector array is mated with a preamplifier on a single silicon chip, providing sensing and...
piezoelectric motion systems
Piezoelectric motion systems are mechanical systems that utilize piezoelectric materials to generate controlled motion or...
reflectance confocal microscopy
Reflectance confocal microscopy (RCM) is a non-invasive imaging technique that allows for high-resolution, in vivo imaging...
photomicrographic camera
A still or motion-picture camera designed to photograph through a microscope. Photomicrographic equipment usually contains a...
Johansson geometry
A design for bent crystal monochromators in which spacing is constant along any circular arc terminating at the two foci and...
Fresnel lens
A Fresnel lens is a type of optical lens that consists of a series of concentric grooves or steps carved into a flat, thin...
digital camera
A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film...
concave grating
A reflecting grating ruled on a concave spherical surface that not only disperses the light but focuses the spectrum. The...
microscopy
Microscopy is a scientific technique that involves the use of microscopes to observe and study objects that are too small to...
Fresnel number
In a lens, the square of the radius of its aperture divided by the product of the focal length and the wavelength. It...
collimator
An optical instrument consisting of a well- corrected objective lens or mirror with a light source and or object/image (i.e....
infrared image tube
An image converter that produces a visible image based on the infrared emittance of the object. The infrared energy is...
split lens
A close-up lens, semicircular in shape, that is mounted in front of a conventional lens focused at infinity. The result is...
scalar diffraction theory
Scalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly...
custom optic
A custom optic refers to an optical component that is designed, manufactured, and tailored to meet specific requirements or...
two-photon fluorescence
This results from the simultaneous absorption of two photons, each having half the energy needed for excitation and...
electron-beam drilling
The use of a tightly focused beam of electrons to drill minute holes in substances. The drilling is accomplished by the...
electron telescope
An instrument that serves to produce an enlarged electron image on a fluorescent screen by focusing an infrared image of a...
aperture ratio
The ratio of the lens aperture to its focal length (1/f/#).
substage condenser
In a microscope, the optical assembly that focuses light on the specimen and into the objective.
optoelectronics
Optoelectronics is a branch of electronics that focuses on the study and application of devices and systems that use light...
minimum spot size
The smallest linear diameter to which a laser or other beam of radiant energy is capable of being focused, depending on the...
diopter movement
The adjustment of the eyepiece of an instrument to provide accommodation for the eyesight differences of individual...
gas focusing
 laser crystal
A laser crystal, also known as an active medium or gain medium, is a solid-state material used in the construction of...
interchangeable lens
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...
telephoto ratio
In a telephoto lens, the ratio of the overall length to the focal length of the lens. It is generally about 0.8 to 0.9 in...
electron image tube
A cathode-ray tube that increases the brightness or size of an image or forms a visible image from invisible radiation. The...
scanning electron microscope
A scanning electron microscope (SEM) is a powerful imaging instrument used in scientific research, materials...
computer-generated holographic scanner
A phase reflection scanner that eliminates the need for a complex translation device while maintaining a high-energy-density...
eye-safe laser operation
Wavelengths between 400 and 1400 nm (VIS to NIR) are focused onto the retina by the cornea. Because the retina is sensitive...
volumetric imaging
Volumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of...
aplanatic surface
An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and...
Wehnelt cylinder
Also known as cathode-ray tube grid or shield. A cylindrically shaped electrode that, containing the cathode of a...
correlated double sampling
A technique for removing thermal noise and drift from focal plane assemblies by sampling the system output between views of...
compensating glass
Also known as clear glass or clear filter. The clear glass plate is used to simulate a filter, in converging or diverging...
concave and convex spherical mirror
Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These...
anamorphic system
An optical system with different focal lengths or magnification levels in perpendicular planes to the optical axis.
alignment telescope
An optical tooling instrument consisting of an objective lens, a focusing lens, an optical micrometer, a reticle and an...
focus lamp
An incandescent or carbon arc lamp designed with a stable and compact arc or filament that permits it to be used as a light...
image iconoscope
A camera tube similar in design to the iconoscope. However, the image formed in the image iconoscope is projected on a...
depth of convergence
A critical image parameter in applications where object position may change dynamically relative to the imager; this is a...
achromat
An achromat, in the context of optics, refers to a type of lens or lens system designed to reduce chromatic aberration....
measuring wedge
A wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that...
vertex power
The reciprocal of the back focal distance of a spectacle lens.
histology
Histology is the branch of biology and medicine that involves the study of the microscopic structure of tissues and organs...
astronomical mirror
An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It...
confocal scanning microscope
A microscope design that involves apertures inserted in conjugate plane positions inside the microscope, with one aperture...
sextant
A handheld navigational instrument used to measure the elevation angle of celestial bodies such as the sun. An image of the...
radial gradient
In gradient index optics, a gradient profile in which the index varies in a direction perpendicular to the optical axis....
blur circle
A blur circle refers to the out-of-focus region in an image captured by an optical system. When an object in a scene is not...
telecentric lens
There are three types of telecentric lenses: -Image-space telecentric lenses are those in which the aperture stop is...
total insert
The lateral distance between a vertical line drawn through the geometrical center of the distance portion of a multifocal,...
blooming
The loss of focus of a camera sensor because of excessive brightness, characterized by the enlargement of spot size and...
focusing coil
A coil used to focus an electron beam by the generation of a magnetic field parallel to the beam.
optical dynameter
A small low-power microscope or magnifier with a scale that is used to measure the exit pupil diameter and eye relief on...
oblique spherical aberration
coma, fifth order aberration with on-axis focal point variation with incident off axis ray height position
perovskite
The term perovskite refers to a specific crystal structure commonly found in various materials. Perovskite structures have a...
projection x-ray microscope
A microscope that uses an extremely fine x-ray focal point to produce an enlarged photographic image of a sample. Also known...
astronomical telescope
An astronomical telescope is a type of optical instrument designed to gather and magnify light from distant celestial...
ocular accommodation
The physical adaption of the eye lens, by means of ciliary muscle contraction, in order to maintain a clear, in focus image...
vertometer
A device that measures the back focal length or vertex power of a lens.
MTF optimization
Computerized lens design algorithm that permits the lens MTF characteristic to be included and controlled during the...
t number
The equivalent f number of a fictitious lens that has a circular opening and 100 percent transmittance, which would give the...
stereoscope
A small instrument containing a picture support and a pair of magnifying lenses so arranged that the left eye sees only the...
conjugate points
The two points on the principal axis of a mirror or lens so positioned that light emitted from either point will be focused...
varifocal
phase-contrast microscope
A microscope that has an annular stop in the lower focal plane of the condenser, and a quarter-wave retarding and absorbing...
Kerr effect
The Kerr effect, named after the physicist John Kerr who first observed it in 1875, is a nonlinear optical phenomenon where...
wafer tube
An image intensifier tube in which the photocathode and the output of the microchannel plate are proximity-focused on the...
point-focusing collector
A device used in solar systems to direct mirror-reflected sunlight to a heat absorber and heat-driven engine, which turns a...
infrared light source
An infrared light source is a device that emits light in the infrared spectrum, which lies beyond the visible spectrum of...
wood lens
A type of radial gradient lens that can focus light even though its surfaces are flat.
telephotography
1. A method of photographing distant objects with a lens of long focal length. 2. The reproduction of photographs over a...
revolving lens fiber optic scanner
A sequential scanning device, utilizing a revolving lens, in which the cathode-ray tube image is transformed into a circle...
laser diode module
A laser diode module is a compact device that incorporates a laser diode, optics, and often other components into a single...
principal focus
aspheric lens
An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical...
Z-scan
A technique for determining the nonlinear optical properties of a sample material by moving the sample through a focused...
laser
A laser, which stands for "light amplification by stimulated emission of radiation," is a device that produces coherent and...
spot diagram
A method of evaluating image quality whereby a large number of rays are traced through a lens from a single object point,...
Nipkow disc scanner
A device consisting of a disc with a spiral arrangement of holes that is used to convert visible patterns into electrical...
focal length
The focal length of a lens is the distance between the lens's optical center (or principal point) and the image sensor or...
adaptive optics
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of...
x-ray image intensifier
An image intensifier that consists of an evacuated tube with a large input phosphor screen at one end. The phosphor screen...
trochoidal mass spectrometer
A magnetic-deflection mass spectrometer that has an electrostatic field placed perpendicularly to its magnetic field,...
total image runout
Image displacement by a decentered lens, rotated on a chuck whose axis of rotation passes through the geometrical center of...
spurious resolution
A phenomenon that causes the details in an image to appear at a spatial frequency higher than that at which the contrast...
focal plane shutter
A shutter having one or more roller blinds of material with a variable slit that moves across the back of the camera when...
edge-emitting LED
An edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the...
extreme ultraviolet
Extreme ultraviolet (EUV) refers to a specific range of electromagnetic radiation in the ultraviolet part of the spectrum....
pulse amplification
The compression and intensification of a laser pulse of a specific width into a smaller pulse width. A spherical cavity, in...
infrared camera
An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the...
Barlow lens
A negative lens used to increase the effective focal length of a telescope objective.
microlens array
A microlens array is a grid-like structure composed of numerous small lenses, typically arranged in a regular pattern. Each...
spheric lens
A spheric lens, also known as a spherical lens, is a type of optical lens with at least one surface that is part of a...
Hartmann test
A test for spherical aberration, coma or astigmatism in which incident rays from a point source are isolated by small holes...
effective f number
For a lens with an obscured or noncircular aperture, the focal length divided by the effective aperture.
reduced focal length
The ratio of the first focal length of a lens to the refractive index of the medium containing the incident light; the ratio...
ammonia pellets
Charged frozen pellets that are rapidly bombarded with a focused high-power laser to form a dense plasma that can be heated...
near-field scanning optical microscope
A scanning probe microscope that analyzes the surface of a specimen by recording the intensity of light as it is focused...
spherical microintegrated lens
A tiny lens (as small as 100 µm in diameter) used to focus light on charge-coupled devices, formed by heating a...
back focal length
The distance from the final optic within a system to the rear image point of the system. See focal length.
least circle of confusion
The circle of confusion is a defocused or aberrated image of a point. Focus is generally set where the diameter of this...
double-focusing mass spectrometer
A mass spectrometer utilizing both radial electrostatic and magnetic field analyzers to improve the focusing and increase...
crystalline lens
The internal lens of the eye. It is semielastic to permit changes in its power when focusing on objects at near distances.
far point (of vision)
The object distance at which the eye is focused with the eye lens in a neutral or relaxed state.
point light source
1. With respect to angular subtense, a source of light, such as a star, that is very small. In a lab, a point source may be...
infrared lens
An infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating...
photon sieve
A photon sieve is an optical device used in the field of optics and imaging. It's designed to focus and shape light,...
metabolic imaging
Metabolic imaging refers to the visualization and quantification of metabolic processes within living organisms, tissues, or...
laser trapping
A technique for confining atoms, molecules or small particles within one or more laser beams. This can be accomplished...
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,...
laser tweezers
A technique based on the principles of laser trapping and used to manipulate the position of small particles by gradually...
pupil
1. In the eye, the opening in the iris that permits light to pass and be focused on the retina. 2. In a lens, the image of...
electron diffraction camera
A special evacuated camera equipped with means for holding a specimen and bombarding it with a sharply focused beam of...
two-photon polymerization
Two-photon polymerization (TPP) is a technique used in additive manufacturing, specifically in the field of 3D printing. It...
Airy disc
The central peak (including everything interior to the first zero or dark ring) of the focal diffraction pattern of a...
laser-mediated gene transfer
Laser-mediated gene transfer refers to a technique in molecular biology and genetic engineering that utilizes lasers to...
paraxial focus
Focus derived from paraxial data.
angle of convergence
An angle formed by the lines of sight of both eyes when focusing on an object. Also, the rate at which a ray approaches the...
quadrupole lens
A device used in electron microscopes and particle accelerators to focus electron beams by the arrangement of four...
galvanometric scanner
A galvanometric scanner, also known as a galvanometer scanner or galvo scanner, is a type of optical scanning device used to...
ring micrometer
A flat, round micrometer that is placed in the focal plane of a telescope to measure difference in right ascension and...
major
A blank to which a piece of glass of a different refractive index will be fused to form a multifocal lens.
fiber-coupled LED
A fiber-coupled LED (light-emitting diode) refers to an LED device that is optically coupled to an optical fiber for the...
topological photonics
Topological photonics is a branch of physics and optics that explores the application of topological concepts to the...
thermograph
The instrument used to collect thermal radiation information on an object by scanning. It consists basically of a detector,...
fluorescence correlation spectroscopy
A powerful method, referred to as FCS, for determining the average diffusion coefficients of fluorescent molecules in...
liquid mirror
A mirror composed of liquid, taking advantage of the parabolic shape of a spinning liquid and the fact that the mirror's...
x-ray lithography
A method of projecting integrated circuit patterns on a silicon wafer using x-ray wavelengths focused through a special mask.
axicon
An optical device that produces a line image lying along the axis from a point source of light; therefore, it has no...
Rowland circle
The circle that contains the slit, grating and primary astigmatic focus of a concave diffraction grating.
nanophotonics
Nanophotonics is a branch of science and technology that explores the behavior of light on the nanometer scale, typically at...
parfocal eyepiece
One eyepiece of a set having equal distances from their mounting interface to their image plane, permitting freedom to...
mirror
A smooth, highly polished surface, for reflecting light, that may be plane or curved if wanting to focus and or magnify the...
optofluidics
Optofluidics is an interdisciplinary field that combines principles from optics and fluidics to create devices and systems...
free-space optical interconnect
A type of internal photonic connection in an integrated circuit in which a holographic grating is used to focus light at...
metalens
A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light...
focal plane
A plane (through the focal point) at right angles to the principal axis of a lens or mirror; that surface on which the best...
diopter
A unit of optical measurement that expresses the refractive power of a lens or prism. In a lens or lens system, it is the...
parfocal lenses
Lenses that have identical flange focal distances and can be interchanged.
modulated zone plate
A zone plate produced by a computer and having a binary structure that can be etched into a chromium or quartz layer. It...
conduction welding
A type of laser welding of thin materials using a defocused or low-power carbon dioxide laser beam. The energy is absorbed...
intensified charge-coupled device camera
An intensified charge-coupled device (ICCD) camera is an advanced imaging device that combines the capabilities of both an...
laser velocimeter
A system that uses a continuous-wave laser to measure the velocity of an object by focusing the laser beam on the object,...
focal plane array
A linear or two-dimensional matrix of individual detector elements, typically used at the focus of an imaging system.
lens testing equipment
Lens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance,...
myopia
A vision defect commonly referred to as nearsightedness. The defective condition results when the image of a distant object...
effective focal length
 Shack-Hartmann wavefront sensor
The Shack-Hartmann wavefront sensor is an optical device used for measuring the wavefront aberrations of an optical system....
retrofocus lens
Also known as reversed telephoto lens. A lens consisting of an ordinary objective with a negative component near its front...
optical beam steering
Directing an optical beam in varying directions by varying reflection, refraction, focusing and diffraction methods.
countersink
The concave portion of a surface, formed on a blank, on which the disk of higher refractive glass will be fused to form a...
rear operating aperture
The restricting opening at the rear of a lens or prism that is commonly defined as the maximum diameter of the emergent cone...
minimum object distance
Minimum object distance, often abbreviated as MOD, refers to the closest distance at which a camera lens or optical system...
process lens
A lens that is symmetrical and designed to work between 1:1 and about 4:1. It covers a field of about ±20° at f/8...
soft-focus lens
A lens that exhibits spherical aberration when used at large aperture settings, and that forms an image with a slightly...
relative aperture
The ratio of the diameter of the entrance pupil in an optical system to the equivalent focal length of that system. The...
triangulation
A method of measuring distance by recording a single scene from two points of perspective. Surveying instruments can be...
front vertex focal distance
The distance between the front focal point and the vertex of the front surface.
dichroic mirror
A dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that...
immersed detector
A radiation detector with its active medium mounted within a lens that focuses the radiation signal. The improvement in...
apochromat
An apochromat, often referred to as an apochromatic lens or apochromatic objective, is a type of optical system designed to...
focal collimator
A collimator having, at one end of a tube, an objective lens, and at the other, a reticle with a pair of spaced lines...
guided wave
A wave in which energy is focused near a boundary separating materials having different properties. Propagation of the wave...
inset
The horizontal distance between the 90° meridian of a bifocal lens and the geometrical center of the segment.
reflecting spectrograph
A solar spectrograph that uses long focus concave mirrors as its collimator and camera element.
mechanical tube length
In a microscope, the physical distance between the focal points of the objective lens and the eyepiece. The standard tube...
chromatic aberration
Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a...
nodal testing
The measurement of first- and higher order properties of a lens and its formed image, including effective focal length, back...
magnifier
A lens or lens system that produces an enlarged virtual image of an object placed near its front focal point.
Crayford focuser
A high-quality focuser that uses rollers rather than gears and offers smooth, precise motion while reducing or eliminating...
beam expander
A system of optical components designed to increase the diameter of a radiation beam. Usually an afocal system.
light diffusion
Light diffusion refers to the process by which light is scattered or spread out in various directions as it interacts with a...
terahertz spectrometer
A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz...
end-fire coupling
End-fire coupling refers to a method of coupling energy into or out of a waveguide, transmission line, or antenna, where the...
perfect lens
A theoretical, ideal lens capable of producing perfect images. Used as a lens design and analysis tool to image collimated...
electron-beam film scanning
The method by which photographic film is scanned by an electron beam. One technique uses the uniform light of a television...
lenticular stereo photography
A type of stereoscopic photography in which a pair of lenses focuses a pair of images, relative to the positions of the two...
conjugate autofocus system
A system that determines whether an image is in or out of focus by means of a source of illumination at the conjugate focal...
electron probe microanalysis
An analytical technique used to determine the nature of extremely small samples by forming the x-ray spectrum of the samples...
coupled rangefinder
A rangefinder on a camera that is integrated with the focusing mechanism so that when an object's range is determined, the...
flat-field lens
A lens that focuses on a flat plane because its field of curvature is close to zero.
unipotential electrostatic lens
A simple electrostatic lens with a focus controlled by a single potential difference.
telescope
An afocal optical device made up of lenses or mirrors, usually with a magnification greater than unity, that renders distant...
light sheet fluorescence microscopy
Also known as single plane illumination microscopy (SPIM), this process was designed for imaging of sensitive samples and...
orthographic camera
A camera designed with a telecentric optical system and a narrow field of view; the telecentric optical system (placement of...
laser triangulation
A technique that uses a solid-state laser and a detector to determine an object's relative distance to the system. The laser...
image dissector tube
An electron tube that is used as a camera tube for a television system. When the picture to be transmitted is focused on a...
petrographic microscope
A microscope equipped with a polarizer, an analyzer and a Bertrand lens to focus on the upper focal plane of the objective....
front-cell focusing
A method of focusing an optical system by moving the front component (the lens closest to the subject) to change the...
spread function
The distribution of energy about the image of a point source in the focal plane of an optical system.
magnetic lens
An arranged series of coils, magnets or electromagnets disposed in such a way that the resulting magnetic fields generate a...
segment
In multifocal spectacles, a term used to denote glass with a high refractive index that has been fused to the blank and...
field of collimator
An expression of the tolerance of decentration of a laser diode from the optical axis: the region around the axis in the...
Fresnel zone plate
A zone plate in which the zones are alternately transparent and opaque to specific radiation, and coarse enough so that no...
gradient-index profile
The term gradient-index profile refers to a specific type of refractive index distribution within an optical material. In...
x-ray tube target
Also known as an anticathode. An electrode or electrode section that is focused upon by an electron beam and that emits...
parfocal
Having coincident focal points.
point of fixation
An established point on which the observer's eye is focused.
fluorescence lifetime imaging
Fluorescence lifetime imaging (FLIM) is an advanced imaging technique that provides information about the lifetime of...
cross wire
Fine lines, wires or threads used in the focal plane of many optical instruments to point out and locate particular objects...
image orthicon
A camera tube widely used in television broadcasting. It consists of three sections within a single vacuum envelope. 1. A...
high-speed movie camera
A camera designed to record at rates exceeding 50 fps. For frame rates up to about 500 fps, an ordinary pull-down mechanism...
afocal
An optical system with object and image points at infinity. Literally, "without a focal length."
liquid crystal on silicon
Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based...
telephoto power
The ratio between the focal length of a lens having a longer focal length than that of the standard lens used with a camera,...
wide-angle lens
A wide-angle lens is a type of camera lens that has a shorter focal length than a standard or normal lens, allowing it to...
conjugate ratio
The ratio between the object distance and the image distance measured along the principal axis of a lens or mirror. An...
image intensifier
An image intensifier, also known as an image intensification tube or image intensification device, is a specialized...
optical coherence tomography imaging system
Optical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain...
lens mount
The metal tube that maintains the optical components of a lens in proper relationship. Some lenses are mounted in metal...
paraboloidal mirror
A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a...
machine learning
Machine learning (ML) is a subset of artificial intelligence (AI) that focuses on the development of algorithms and...
absolute magnification
The value of the distance of distinct vision, minimum focusing distance or near point, divided by the focal length of the...
white-light continuum
An extremely wide emission spectrum generated by the nonlinear effects created when a high peak power from a short-pulse...
circle of confusion
The image of a point source that appears as a circle of finite diameter because of defocusing or the aberrations inherent in...
laser microscopy
Technique using functional optical microscope with the addition of a coherent source collinear with the image path. The...
Sturm interval
The distance between two focal lines in an astigmatic image produced by a lens or mirror.
spherical aberration
Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface...
ophthalmology
Ophthalmology is a branch of medicine that focuses on the anatomy, physiology, and diseases of the eyes and visual system....
laser surgery
Laser surgery refers to a medical procedure in which a laser, or focused beam of light, is used as a precision tool to cut,...
standard lens
A lens whose focal length is roughly equal to the diagonal of the negative format of the camera on which it is mounted.
directed energy
Directed energy refers to a type of energy that is emitted and transferred in a controlled direction. The term is often...
camera shutter
An apparatus, designed for use with a camera, that is used to rapidly open the path from lens to film, to maintain the...
principal point of focus
telephoto lens
A compound lens so constructed that its overall length is equal to or less than its effective focal length.
focus
1. The focal point. 2. To adjust the eyepiece or objective of a telescope so that the image is clearly seen by the observer....
machine vision lens
A machine vision lens is a specialized optical lens designed for use in machine vision systems, which are used for automated...
SELFOC fiber
Derived from "self-focusing,'' Nippon Sheet Glass Co. (NSG) of Japan's trade name for graded-index fiber rods with parabolic...
aspheric mirror
An aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical...
light field
The term light field refers to the spatial distribution of light rays traveling in all directions through a given space. It...
film platen
A mechanism in a camera designed to position the film in the focal plane for exposure.
core-coupled lens
A semispherical or conical lens created directly on the core of an optical fiber to focus light from a laser into the fiber...
optical assembly
An optical assembly refers to a collection of optical components that are carefully arranged and aligned to perform a...
laser optics
Laser optics refers to a broad category of optical components and systems designed for manipulating and controlling laser...
rear focusing
A type of internal focusing in which only the lens elements closest to the rear of the lens barrel are moved.
free-electron laser
A free-electron laser (FEL) is a type of laser that generates coherent, high-intensity electromagnetic radiation by using a...
catadioptric imaging system
A system that uses both reflection and refraction to achieve its focal power. While the relative powers of the lenses and...
intermediate image
In an optical system with a series of lenses, images formed prior to the final focal plane.
autofocus system
A means of adjusting the sharpness of an image automatically, with a sensor for estimating distance or contrast and a drive...
lens speed
Also known as f number, lens speed is commonly represented as the ratio of the focal length to the diameter of the lens....
Seidel aberrations
Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and...
electromagnetic focusing
beam profiling
Beam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It...
stereomicroscope
Wide-field, low-magnification device that consists of two compound microscopes focused on a single object, producing an...
optical tweezers
Optical tweezers refer to a scientific instrument that uses the pressure of laser light to trap and manipulate microscopic...
focusing corner cube
A retroreflector that can focus a beam of light, with one planar reflective surface, one spherical and a third that is...
meta-optics
Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication,...
image converter
An electron tube that employs electromagnetic radiation to produce a visual replica of an image produced on its cathode....
catoptric light
Light that is directed or focused by means of curved reflective surfaces.
biplanar image tube
Also called proximity focus image intensifier. A compact image intensifier that utilizes a microchannel plate...
tip-enhanced Raman scattering
Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial...
saccadic motion
The movement of the eye as it focuses on details of a scene. Some imaging systems mimic this movement by small, rapid...
Abbe condenser
A two-lens arrangement intended to image light into a microscope slide sample. The primary aberrations present are red and...
tomography
Technique that defocuses activity from surrounding planes by means of the relative motions at the point of interest.
camera obscura
A forerunner of the modern camera, this instrument had a focusable lens that produced a sharp image on the enclosure...
medical lasers
Medical lasers are devices that produce intense beams of light with specific characteristics and properties, which are used...
photographic field
The maximum angle of view that can be recorded by a camera. Field is a function of lens focal length and film format.
cylindrical lens
A cylindrical lens is an optical component that has different curvatures along its two orthogonal axes, resulting in a shape...
electrostatically focused image tube
An image intensifier that uses electrostatics to amplify and focus the electronic image.
emmetropia
The normal condition of vision where an object at infinity is in sharp focus with the eye lens in a neutral or relaxed state.
field tilt
The angle measured between the focal surface containing the image and a plane normal to the optical axis.
mirror lens
An image-forming system having curved mirrors in place of transparent glass components. Mirror lenses are commonly used for...
cardinal points
Focal, nodal or principal points of a lens. If the respective distances of the object and image are measured from the...
segment width
In spectacle lenses, the lateral measurement of a multifocal segment at its maximum width.
converging lens
Also known as convergent lens or convex lens. A lens that converges an incident bundle of rays to a focus.
equivalent air path
When a block of glass (prism, window, filter, etc.) is placed into a converging light bundle, it increases the physical...
panoramic camera
A camera designed to form a continuous record of an expansive section of the horizon. The typical panoramic camera is...
microscope stage
The component of a microscope on which the sample or slide to be examined is placed. Depending on the design of the...
microscope
An instrument consisting essentially of a tube 160 mm long, with an objective lens at the distant end and an eyepiece at the...
Bertrand lens
A small convergent lens, located between the objective and eyepiece of a microscope, that focuses an image of the upper...

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