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Trioptics GmbH - Worldwide Benchmark 4-24 LB
surface Dictionary Terms

catoptric light
Light that is directed or focused by means of curved reflective surfaces.
fiber laser
A fiber laser is a type of laser in which the active gain medium is an optical fiber doped with rare-earth ions such as...
optical testing instrument
An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and...
low Earth orbit
Low Earth orbit (LEO) refers to a region in space that is relatively close to Earth's surface, typically characterized by...
cladding
The low-refractive-index material that surrounds the core of an optical fiber to contain core light while protecting against...
infrared detector
An infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible...
vertex
The point of intersection of the optical axis with any centered optical surface.
probe card
A probe card is a testing device used in the semiconductor manufacturing industry to evaluate and test the electrical...
meta-optics
Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication,...
vertical-cavity surface-emitting laser
 threshold wavelength
The greatest wavelength of radiation for a specified surface for the emission of electrons.
uncut
A term describing lenses with both surfaces finished but not yet cut to any form.
Brewster's angle
For light incident on a plane boundary between two regions having different refractive indices, the angle of incidence at...
Casimir force
The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged...
deep
A concave surface that has too much negative power; i.e., its radius of curvature is too short. This condition can be...
deep ultraviolet
Deep ultraviolet (DUV or deep-UV) refers to a specific range of ultraviolet light with shorter wavelengths than those in the...
stylus indicator alignment
A method used in surface quality testing for accurate positioning and rotation of metal spheres about an axis or fixed point...
plane holographic grating
The generation of a grating on a flat surface by means of a series of interference fringes formed by a holographic process....
half silvered
Describing a surface that is coated with a film of metal of such thickness that it transmits about one-half of the incident...
optical profiler
Also known as a white-light interferometer. Measures surface texture and shape from nanometer-scale roughness to...
adaptive optics
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of...
reflecting prism
A prism having several plane polished surfaces, some to transmit light, some to reflect light, and some to serve both...
angle of refraction
The angle formed between a refracted ray and the normal to the surface. This angle lies in a common plane with the angle of...
narrow-angle dark-field illumination
An imaging system designed to highlight small deviations in a planar reflective object such as a mirror. The system can be...
extraordinary ray
A ray that has a nonisotropic speed in a doubly refracting crystal. It does not necessarily obey Snell's law upon refraction...
intensified charge-coupled device camera
An intensified charge-coupled device (ICCD) camera is an advanced imaging device that combines the capabilities of both an...
plano surface
A lens or mirror surface that is perfectly flat.
phase mask
In optics and photolithography, a phase mask refers to a device that modifies the phase of light waves passing through it....
optical cements and adhesive
Optical cements and adhesives are specialized materials used in the assembly and bonding of optical components in optical...
cladding ray
A ray that is reflected into the core of an optical fiber from the outer surface of the cladding.
hardness
In the most general sense, the resistance of a solid surface to damage.
optical table
An optical table, also known as an optical bench or an optical breadboard, is a specialized platform used in optics...
concave grating
A reflecting grating ruled on a concave spherical surface that not only disperses the light but focuses the spectrum. The...
orange peel
In the context of imaging, particularly digital imaging and printing, "orange peel" refers to a texture or visual distortion...
green block
A porous ceramic substance that is ground to a given optical form and on which a polished plate of glass is sagged by heat...
milling
An automatic surface-generating process involving the removal of a material from a given surface. Optical milling typically...
diffuse reflection
Nonspecular reflection from a rough surface.
azimuth angle
1. In astronomy, the angle measured clockwise (eastward) in a horizontal plane, usually from north (true north, Y-north,...
footprint
1. The sector of the Earth's surface registered upon a remote sensing device in a satellite. 2. The amount of space occupied...
x-ray phase contrast microscopy
Used for high-resolution surface study with subnanometer resolution. XRIM uses interfacial phase contrast with application...
gray
1. A measure of absorbed dose, equal to the energy imparted by ionizing radiation to a mass of matter corresponding to 1 J...
visual photometer
A photometer that permits visual comparison of the luminance of two surfaces.
honeycomb table
An optical test table made up of two outer layers or "skins'' bonded to either side of a honeycomblike core, usually of...
angle of deviation
The angle through which a ray of light is deviated by a refracting or reflecting surface, or a prism; the angle between an...
ultraviolet reflectance
Ultraviolet reflectance refers to the ability of a material or surface to reflect UV light. Ultraviolet light is...
beauty defect
A defect on or in an optical element that does not appreciably impair the function of the surface.
vacuum etching
Also known as cathodic etching. Surface etching achieved by bombarding an evacuated surface with gas ions.
bitoric lens
A lens, both surfaces of which are ground and polished into a toric or cylindrical form.
cryopump
A vacuum pump in which pressure is reduced by condensing gases on surfaces cryogenically cooled to about 20 K (liquid...
riez photodiode
A photodiode having a conducting grid that covers the surface of the photodiode junction and intercepts and wastes some of...
transmission sphere
A precision lens designed to convert the plane wavefront output of an interferometer to a spherical wavefront for the...
ocular surface
That surface of a lens located nearest to the eye.
brightness meter
An instrument for measuring the brightness (luminance) of a scene. It may be a spot meter, covering an area of a degree or...
cementing surface
The surface of an element of a compound lens that will produce the cemented interface. The curves of this interface are...
primary coating
In a waveguide, the material in intimate contact with the cladding surface, applied to preserve the integrity of that...
trepanner
A tool used in cutting circular holes around a center. Also, a laser cutter in which the beam moves in relation to the cut...
surface acoustic wave
An acoustic wave that propagates along the surface of a solid and decays exponentially with substrate depth. Also called a...
matt
A term used to describe a nondirectionally diffusing surface that, when illuminated, appears equally bright from all angles....
surface wave
A wave that is guided by the interface between two different media or by a refractive index gradient in the medium. The...
crust
A stain in a glass surface.
spherometer
An instrument for measuring the radius of curvature of a spherical lens or mirror surface. It may consist of a ring resting...
cartesian lens
A lens, one surface being a cartesian oval, that produces an aplanatic condition.
sputtering target
A sputtering target is a solid material used in the process of physical vapor deposition (PVD), specifically sputtering....
marcuse loss theory
A theoretical analysis of radiation loss from planar optical waveguides due to scattering by surface irregularities/surface...
photosite
A small section of the surface of a sensor corresponding to a single pixel in the image.
centered lens system
A lens system in which the centers of curvature of all surfaces fall on a common axis.
concave
Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In...
photoelectron microscopy
Surface analysis by means of photon induced electron emission. PEM methods provide high lateral resolution of the observed...
electro-optic modulator
An electro-optic modulator (EOM) is a device used to modulate the amplitude, phase, or polarization of light waves using an...
law of reflection
The law stating that the angle of reflection is equal to the angle of incidence, the incident ray, reflected ray and normal...
telephotometer
An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small...
chip-on-board lights
Chip-on-board (COB) lights refer to a type of LED lighting technology where multiple LED chips are directly mounted onto a...
3D laser triangulation
3D Laser Triangulation - A technology that allows sensors to probe the surroundings. Laser triangulation systems have an...
penta prism
A five-sided prism containing two reflecting surfaces at 45° to each other, and two refracting faces perpendicular to...
semilenticular screen
A projection screen having vertical ribs or flutes set into a plastic surface.
curvature of field
A lens aberration that causes a flat object surface to be imaged onto a curved surface rather than a plane.
surface error
The departure of an optical surface from its required tolerance or figure.
abrasion mark
Optical surface damage due to abrasive rubbing. Abrasion damage affects are less than the thickness of the optical coating...
Mangin mirror
A double-surfaced catadioptric spherical mirror whose spherical first surface consists of a negative meniscus (concave) lens...
optical manufacturing tools and machinery
Optical manufacturing tools and machinery encompass a wide range of equipment, instruments, and systems used in the...
gloss
Property of a surface which, because of directional reflection, is responsible for the degree to which reflected highlights...
global radiation
The total radiation, both solar and diffuse sky, that is incident to a unit's horizontal surface.
illuminated table
A desklike apparatus with an opal glass surface illuminated from beneath by fluorescent tubes. It is equipped with roll...
infrared modulated ellipsometry
A direct method of measuring refractive index that works best with flat-surfaced samples (i.e., those that are not dependent...
polisher pressing
The process of forming a polisher by pressing it with an optical surface.
tip-enhanced Raman scattering
Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial...
Q
The figure of merit of a resonator, defined as (2p) x (average energy stored in the resonator)/(energy dissipated per...
CID camera
CID, or charge injection device, camera refers to a type of imaging device that utilizes a specific kind of solid-state...
laser drill
High power laser ablation device that by pulsed operation produces holes of controllable dimension on the scale of microns....
coaxial gas
A jet of inert gas along a laser welding beam's axis that cools, protects or cleans the work surface.
CCD image sensor
A CCD image sensor, or charge-coupled device image sensor, is a type of electronic device used to convert optical images...
Ramsden eyepiece
An eyepiece consisting of two planoconvex lenses of the same focal length, with facing convex surfaces.
albedo
The ratio of radiant energy reflected from a rough surface to that incident on it. Usually, the radiant energy is total...
vertical-cavity laser diode
A type of surface-emitting laser diode that uses dielectric mirrors to produce surface emission. The laser cavity is...
optical materials
Optical materials refer to substances or compounds specifically chosen for their optical properties and used in the...
quality, surface
 optical lever
A device used to detect and measure small amounts of rotation. The rotating object contains a reflecting surface from which...
surface-enhanced Raman scattering
Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that enhances the Raman scattering signal of...
burn
A surface imperfection caused by a polisher running dry too long. It occurs with felt or plastic polishers, and may appear...
transmission electron microscope
A transmission electron microscope (TEM) is a powerful microscopy technique that uses a beam of electrons to create...
antistatic coating
An electrically conductive layer for carrying off static charges that might accumulate on a surface.
stylus profilometer
A measuring instrument used for surface profiling and quantifying the roughness of a material. The stylus is placed on the...
injection molding
A method of producing high-quality plastic optics in large volumes by injecting the heated, liquified plastic at high...
flat-field frame
A frame taken with a CCD camera of a surface that is evenly illuminated by diffuse light. This frame shows irregularities in...
thin-film coating
Thin-film coatings are layers of material applied to the surface of an object or substrate, typically to modify its optical,...
thermal interface materials
Thermal interface materials (TIMs) are substances or compounds used to enhance the thermal conductivity between two surfaces...
normal emergence
The emergence of a ray along the normal to the emergent surface of a medium.
laser peening
Laser peening is a surface enhancement technique used to improve the mechanical properties of materials, particularly...
Newton's rings
The series of rings or bands formed when light beams reflected from two polished, adjacent surfaces, placed together with a...
plasmon ion-assisted deposition
Plasmon ion-assisted deposition (PIAD) is a technique used in thin-film deposition processes, particularly in the production...
caustic
A surface that envelops a bundle of rays or bundle of normals to the wave surface. It may be observed as a hollow, luminous...
thermophotovoltaic
Thermophotovoltaic (TPV) refers to a technology that converts heat energy into electricity using the principles of...
Hubner rhomb
A glass rhomb that is used in photometry to compare two illuminated surfaces. This is accomplished by the rhomb's angles,...
reflection
Return of radiation by a surface, without change in wavelength. The reflection may be specular, from a smooth surface;...
centration
In a perfectly centered lens, the mechanical axis (defined by the ground outside the diameter of the lens) is made to be...
dip
The departure of a curved surface from the plane that is tangent to its vertex. See sag.
equivalent wavelength
In surface height measurement of optics with steep slopes, the use of two short visible wavelengths to synthesize a longer,...
photosphere
The apparent surface of the sun or a star from which light appears to radiate.
photoelectric emission
The electron emission from a substance or instrument whose surface has been bombarded by a suitable amount of radiation.
chuck mark
The mark formed when the movement of the lens over the face of the centering chuck abrades the surface.
smart skin
Structural surfaces that incorporate an embedded sensor network capable of detecting flaws within the structure.
reflective spectroscopy
Reflectance spectroscopy is a technique used to analyze the reflective properties of materials across various wavelengths of...
lithography
Lithography is a key process used in microfabrication and semiconductor manufacturing to create intricate patterns on the...
Ritchey-Common test
An interferometric method for describing the surface shape of large coated or uncoated optical flats. The procedure uses a...
enzyme-linked immunosorbent assay
An enzyme-linked immunosorbent assay (ELISA) is a laboratory technique used to detect and measure the presence of specific...
mosaic
One surface of a nonconducting plate that is coated with many minute particles of photoemissive material that are insulated...
image enhancement laser
A semiconductor platelet laser that emits a coherent image by means of plane optical pumping over the platelet surface, and...
clear aperture
The limited light-gathering area of an optical system. The area is normally restricted to an edge or outer surface of an...
multispectral photography
The use of narrow bandpass filters and special photographic emulsions to discern features of a surface that would not be...
resolution
1. In optics, the ability of a lens system to reproduce the points, lines and surfaces in an object as separate entities in...
negative meniscus lens
A negative powered lens with one surface convex and the other concave, the latter having the greater curvature. It also is...
acetate film
Also cellulose acetate film. The emulsion layer applied to the substrate of a photographic surface. The emulsion layer is...
mapping function
In image processing, the mathematical relationships that link pixel brightnesses of input images to those of output images...
optical bench
A support for optical parts comprising a solid bed that permits precise longitudinal movement of one component relative to...
optical cement
A permanent, transparent, and highly transmissive adhesive capable of withstanding extreme temperatures that is applied to...
illuminometer
A photometric instrument used to measure the illumination falling on a surface. It may be photoelectric or visual.
reflector
A type of conducting surface or material used to reflect radiant energy.
polariton
A polariton is a quasiparticle resulting from the strong coupling between photons (light particles) and certain types of...
rolled edge
Also known as a turned-down edge. A rapid change of curvature near the edge in a lens or prism surface.
liquid marble
Liquid marble refers to a unique form of microscale liquid encapsulation, where small droplets of liquid are coated with a...
photogrammetry
Photogrammetry is a technique used to obtain accurate three-dimensional measurements of objects and environments through the...
troland
That level of retinal illuminance resulting when a surface with a luminance of 1 candela/m2 is viewed through a pupil with...
electrowetting display
An electrowetting display (EWD) is a type of electronic display technology that utilizes the principles of electrowetting to...
optical contact
The adhesion of two sufficiently clean and close-fitting surfaces without the use of cement or glue. The optically contacted...
phosphorography
A process used in pyrometry and photothermometry to create a photographic record of a surface's temperature gradients....
photon counter
A device used to evaluate the luminance of a surface by determining the number of photons emitted from a sample surface area.
chip
1. A localized fracture at the end of a cleaved optical fiber or on a glass surface. 2. An integrated circuit.
free-electron laser
A free-electron laser (FEL) is a type of laser that generates coherent, high-intensity electromagnetic radiation by using a...
stroboscopic interferometry
A pulsed interferometer that permits the continuous quantitative mapping of the surface deformation of an adaptive optical...
aerial camera
Camera designed for the imaging of the earth's surface in order to obtain high quality aerial images
lineation
Subsurface linear arrangement of elements of rock that is not mappable; lineation is a one-dimensional characteristic.
atomic force microscope
An atomic force microscope (AFM) is a high-resolution imaging and measurement instrument used in nanotechnology, materials...
fluence
Fluence is a term used in various scientific and technical disciplines to describe the amount of something per unit area....
tunnel luminescence
Light that is emitted from a phosphor film applied to the surface of a three-layer thin film, respectively metal, oxide and...
Geometrical optics
The area of optics in which the propagation of light is described by geometrical lines (or rays) governed by Fermat's...
lidar
Lidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and...
Fabry-Perot mirror
A highly reflective mirror that is usually flat on one surface and curved on the other, and that has silver, gold or...
graded reflectivity mirror
A mirror whose percent reflectance varies as a function of position on the mirror surface.
glitter
The specular reflection of individual parts of a surface.
lens blank
A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which...
thin-film deposition equipment
Thin-film deposition equipment refers to machinery and tools used in the process of depositing thin layers of material onto...
microwave mapping
The pattern of microwave field intensity that can be obtained by detecting the minute expansion of a microwave absorber slab...
leaching
The process of removing some of the constituents of a glass surface by chemical action.
microdensitometer
The fundamental tool of microdensitometry, the microdensitometer is an instrument used for the precise measurement of...
Nicol prism
A prism invented by William Nicol in 1828 that is made of calcite, the end faces of which are ground to an angle of 68°...
heat treating
The process of subjecting glass to temperature cycling to produce physico-chemical reactions that alter its properties....
finesse
For a Fabry-Perot interferometer or etalon, a value for the transmission bandwidth which can be calculated as the ratio of...
vacuum chamber
A vacuum chamber is a sealed enclosure from which air and other gases are removed to create a low-pressure environment,...
grazing emergence
A condition in which an emergent ray is perpendicular to the normal of the emergent surface of a medium.
magnetic force microscope
A variation of the atomic force microscope that operates by scanning a tiny ferromagnetic probe (or a magnetized tip) over a...
photoresist
Photoresist is a light-sensitive material used in photolithography processes, particularly in the fabrication of...
conic refraction
The dispersion of a light ray striking the surface of a biaxial crystal, in which the resulting rays are reflected in a...
axicon
An optical device that produces a line image lying along the axis from a point source of light; therefore, it has no...
concavo-convex lens
A lens with one concave surface and one convex surface; synonymous with meniscus.
free-abrasive machining
The process whereby a rotating wheel carries grains of an abrasive, suspended in a vehicle, across the surface of the...
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...
electron-beam recording
The recording of the information contained in a modulated electron beam onto photographic or silicon resin-coated materials....
Luneburg lens
A dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is...
radiant exitance
The radiant flux per unit area emitted from a surface.
laser ablation
Laser ablation is a process that involves the removal or erosion of material from a target surface using laser energy. This...
total internal reflection fluorescence
Total internal reflection fluorescence (TIRF) microscopy is an advanced fluorescence microscopy technique that leverages the...
germicidal UV
Germicidal ultraviolet (GUV) refers to a specific range of UV radiation that has disinfectant properties capable of killing...
retroreflection
Retroreflection is a phenomenon in optics where light is reflected back toward its source, typically in a direction nearly...
stiction
In positioning, the friction that prevents immediate motion when force is first applied to a body or surface at rest.
computer numerically controlled grinding
Computer numerically controlled (CNC) grinding is a manufacturing process that utilizes computerized controls and precision...
dewetting
Dewetting is a phenomenon in materials science and physics where a thin film or coating spontaneously undergoes a process of...
laser shock adhesion test
A nondestructive test, also referred to as LASAT, that uses a high-energy laser pulse that is targeted on an adhesively...
lens meridian
A line passing through the center of a lens surface, from edge to edge.
exposure
In optics, the total radiant energy incident on a surface-per-unit area. It is equal to the integral over time of the...
dirt hole
A hole filled with dirt such as a polishing abrasive and located in an optical surface. See dig; scratch.
wafer
In the context of electronics and semiconductor manufacturing, a wafer refers to a thin, flat disk or substrate made of a...
point cloud
A point cloud is a set of data points in a three-dimensional coordinate system, where each point represents a specific...
Brace prism
A compound prism composed of two 30° prisms, one of which is partially coated with a suitable opaque metal of high...
plasmonics
Plasmonics is a field of science and technology that focuses on the interaction between electromagnetic radiation and free...
cold cathode
A cathode that emits electrons, not with the influence of heat radiation, but by means of a high-voltage gradient at its...
grinding tool
A tool of cast iron or another suitable medium used with a slurry of silicon carbide, aluminum oxide or emery for grinding...
Martin's diameter
A specific method for measuring the diameter of irregular shaped particles, Martin's diameter is the measured distance...
double-convex lens
A converging lens with both surfaces convex.
metasurfaces
Metasurfaces are two-dimensional arrays of subwavelength-scale artificial structures, often referred to as meta-atoms or...
spherocylinder
A lens or lens surface that is a combination of a sphere and cylinder.
charge-coupled device
A charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital...
scanning tunneling microscope
A high-resolution imaging instrument that can detect and measure the positions of individual atoms on the surface of a...
thermoplastic recording device
A display device having a thermoplastic film as the control layer medium. The film, moving from a playoff reel, is scanned...
microcircuit manufacturing
The formation of transistors, diodes, capacitors, resistors and other electronic elements directly on a flake of silicon by...
narcissus
A defect in infrared systems that appears as a dark circular area on a displayed image, caused by radiation reflecting into...
right-angle prism
A type of 45-90-45° prism used to bend a beam of light through a right angle with the surfaces forming the 90° angle...
object distance
The distance between the object and the cornea, or the first surface of the objective in an optical device.
stressed mirror polishing
A method of polishing an aspheric surface by mechanically distorting the optic while polishing the surface to a perfect...
edge
The flat or angled surface, usually fine-ground, that limits the aperture of a lens or prism surface.
photon tunneling microscope
An instrument in which visible light beyond the critical angle from a metallurgical microscope is focused on a reference...
short-wave radiation
Characterizes the significant solar radiation at the surface of the earth, so named because its spectral range extends only...
surface-emitting laser diode
A semiconductor laser diode that emits light perpendicular to the active region. The output radiation is taken through the...
Porro prism
A 45-90-45° reflecting prism whose surfaces form the 90° angle reflecting the light beam through a total angle of 180°. The...
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...
scatterometry
A measurement technique used for the rapid quantitative evaluation of surface quality based on the detection and analysis of...
gamma-ray spectrometer
An instrument used to detect and measure the energy distribution of gamma rays. It has been used to chart the radioactivity...
center of curvature
The center of the sphere of which the surface of a lens or mirror forms a portion. Each curved surface of a lens has a...
twisted nematic phase
A form of liquid crystal widely used in displays, achieved by sandwiching a liquid crystal material between two substrates...
flow cytometry
Flow cytometry is a powerful technique used in biology and medicine for the quantitative analysis of the physical and...
adhesion
The intermolecular attraction between two surfaces, as between a substrate and a coating; it is an important factor in the...
figure
In optics, the geometrical form of an optical surface.
Lambert's cosine law
Flux per unit solid angle leaving a surface in any direction is proportional to the cosine of the angle between that...
vertical air photograph
An aerial photograph produced when the optical axis of the camera is perpendicular to the surface below.
astronomical mirror
An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It...
rhomboid prism
A reflecting prism that is rhomboidal in shape. It has two parallel transmitting faces, and two parallel reflecting faces;...
photocathodes
Photocathodes are specialized materials or surfaces that exhibit the photoelectric effect, wherein the absorption of photons...
fractional photothermolysis
A laser skin-resurfacing method that creates microscopic thermal wounds referred to as microscopic treatment zones (MTZs),...
photoelectron holography
A technique proposed for studying the atomic structure of crystals by measuring the interference pattern generated when the...
microbubble resonator
A microbubble resonator is a device used in photonics and optical physics for the precise manipulation of light waves. It...
flange focal distance
The distance between the locating surface of the lens mount and the image plane.
surface-enhanced Raman spectroscopy
Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that combines the principles of Raman spectroscopy...
Wolter telescope
A grazing incidence mirror telescope with concentric conic surfaces having a single common point: a paraboloid-hyperboloid...
lap
A metal tool used to grind lenses with loose abrasive (see diamond cutting tool). The functional surface of the lap is...
doma
A primitive crystal possessing two plane surfaces that form a dihedral angle bisected by another plane surface.
Snell's law of refraction
The incident ray, the normal to the refracting surface at the point of incidence of the ray at the surface, and the...
second-side meniscus
The process of grinding the convex surface of a convexo-concave meniscus.
back-coated mirror
A glass substrate that has its rear surface coated with a reflective coating. Also known as a back-surface mirror.
ion emission
The ejecting of ions from the surface of a material.
laser marking
Laser marking is a process in which a laser beam is used to mark or engrave a surface by altering its properties or...
atmospheric refraction correlation
Formulaic compensation to correct laser ranging data for the effects of horizontal refractivity gradients; it requires the...
laser plasma
A plasma produced by the interaction of an intense laser pulse with a material surface. Production of ionized particle with...
phosphor thermometry
A method for remote measurement of the temperature of moving surfaces in harsh environments by using a laser to stimulate...
microphotometer
An instrument capable of measuring the transmitted or reflected luminance from a very small area seen under a microscope....
reticulation
The formation of a distinct, irregular surface pattern on a photographic emulsion due to differential swelling of the...
heat equation
A calorimetric calculation from which the temperature vs. time dependence of any point on a sample can be determined,...
chemical-mechanical polishing
A technique for polishing silicon in which an alkaline suspension containing silicon dioxide particles creates a soft layer...
leading edge spike
In a sequence of laser pulse emissions, the intitial pulse that often helps initiate a reaction at the target surface,...
surface-enhanced Raman optical data storage
A technique of optical storage whereby information is encoded by molecular alterations in the interaction between the...
transfer blocking
A process used to control thickness and parallelism precisely during the production of plane-parallel plates. Elements are...
micropit
A laser-induced scar on experimental bare glass surfaces usually attributable to threshold damage and indicative of isolated...
backlighting
The forming of a clear silhouette of an object by placing a light source behind it. Used in machine vision when surface...
first-surface mirror
 pressing
A blank having basic surface curves attained by forming heat-softened glass that is pressed in a mold.
aspheric mirror
An aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical...
photoacoustic spectroscopy
A method for obtaining the optical absorption spectra of solids, semisolids, liquids and gases. PAS is inherently...
optical assembly
An optical assembly refers to a collection of optical components that are carefully arranged and aligned to perform a...
globulite
A crystal of microscopic size having no definite plane faces and having a globular shape. At the time the crystal is formed,...
stick marks
The fine scratches formed when, in hand centering, the forked stick used to move the lens on the chuck marks the rotating...
evaporation coating
Coating carried out in a sealed chamber evacuated by a mechanical pump in series with an oil diffusion pump to a pressure...
optical coherence tomography imaging system
Optical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain...
Bragg method of crystal analysis
A technique in which a beam of x-rays is directed against a crystal, the atoms of which, because of their lattice...
angle of reflection
The angle formed between the normal to a surface and the reflected ray. This angle lies in a common plane with the angle of...
molded lens
A molded lens is an optical lens manufactured using a molding process, typically involving the shaping of a material, such...
scoring
The cutting of pitch tooling surfaces by an optical technician to permit polishing compounds to flow across the surface of...
grating beamsplitter
A grating beamsplitter is an optical device that utilizes the principles of diffraction to split a beam of light into...
haze
An aggravated form of fog in a polished surface caused by the scattering of light. The defects causing haze are larger than...
wave
1. An undulation or vibration; a form of movement by which all radiant energy of the electromagnetic spectrum is estimated...
ionosphere
The gas of charged particles that begins approximately 50 km above the surface of the Earth and contains a sufficient...
tribology
The science of interfacing surfaces in moving contact, which includes areas such as friction, lubrication and wear.
piezo-optical transducer
A structure consisting of a thin film of liquid crystal sandwiched between light-polarizing filters that have received a...
volumetric imaging
Volumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of...
ellipsometry
Ellipsometry is an optical technique used to characterize the properties of thin films and surfaces. It is based on the...
surface profile
A representation of the shape of a surface, including any roughness or other irregularities. The profile can be generated by...
polygonal mirror
A polygonal mirror, also known as a multifaceted mirror or facet mirror, is a type of optical component used in various...
concentric lens
A lens having surfaces whose centers of curvature coincide.
optics
Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter...
fiber optic window
The face of a cathode-ray tube (CRT) that has a fiber optic sheet attached to its surface. The sheet's fibers are at right...
overcoat
A layer of material applied to a coated surface to protect it from physical or chemical action.
optical axis
The imaginary line passing through both the centers of curvatures of the optical surfaces of a lens or mirror; the optical...
Seidel aberrations
Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and...
coated optics
Optical elements that have been coated with one or more layers of dielectric, or metallic material. These coatings serve to...
optical coatings
Optical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms,...
curvature
The measure of departure from a flat surface, as applied to lenses; the reciprocal of radius. Applies to any surface,...
collimation
1. The process of aligning the optical axes of optical systems to the reference mechanical axes or surfaces of an...
fiber optics
The use of thin flexible glass or plastic fibers as wave guides — or "light pipes" — to channel light from one...
spatially offset Raman spectroscopy
Spatially offset Raman spectroscopy (SORS) is a technique that extends traditional Raman spectroscopy by incorporating...
step index profile
A profile of an optical component, usually a fiber, in which the core is of uniform refractive index and the cladding or...
blaze height
Blaze height typically refers to a parameter in the context of diffraction gratings, which are optical devices consisting of...
laser annealing
Laser annealing is a process that involves using a laser beam to heat and modify the microstructure of a material, typically...
black surface enclosure
An enclosure whose walls are coated to absorb completely all radiation striking them.
spiral
A defect in the cleaved end face of an optical fiber in which the surface changes abruptly.
geodimeter
Trade name referring to an instrument that determines surface distances by measuring the length of time it takes for a...
substrate
A substrate refers to a material or surface upon which another material or process is applied or deposited. In various...
converging surface
The curved boundary between two optical media of different refractive indices, which causes convergence.
optical head
In compact disc and CD-ROM technology, the portion of the drive that projects the laser light onto the surface of the media...
semifinished
A term used to describe a spectacle lens or blank with one surface totally finished.
decentration aberration
An aberration occurring in a lens system when one or more of the centers of curvature of the optical surfaces do not...
filovirus
Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and...
Debot effect
The conversion of an internal latent image into a surface latent image through exposure to infrared radiation. The converse...
bistable display
A matrix-controlled display that has information storage at the display surface, and requires that an element be addressed...
total internal reflection
The reflection that occurs within a substance because the angle of incidence of light striking the boundary surface is in...
corner cube
A corner cube, also known as a corner reflector or retroreflector prism, is a type of optical device used to reflect light...
paraboloidal mirror
A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a...
lapping
1. The process of wearing down the surface of a softer material by rubbing it under pressure against the surface of a harder...
catadioptric imaging system
A system that uses both reflection and refraction to achieve its focal power. While the relative powers of the lenses and...
truing
The process by which a surface is made to conform accurately to a given curvature.
Becke apertometer
Device used to measure the numerical aperture of a microscope, composed of a 14-mm-thick glass block with numerical aperture...
back-surface mirror
 optical testing
Refers to a variety of methods and tools used to determine the surface contour and performance of optical components and...
photovoltaic
Photovoltaic (PV) refers to a technology that converts sunlight directly into electricity using semiconductors. The term...
tip-enhanced Raman spectroscopy
A spectroscopic technique that combines the high chemical specificity of Raman scattering and signal sensitivity provided by...
spectroheliograph
An instrument in which an image of the sun is scanned by the entrance slit of a monochromator, the exit slit simultaneously...
clearing
Also called shining. Grinding and polishing one surface of a blank to permit a more thorough examination for quality.
sand hole
A crude area on the polished surface, produced during coarse grinding, that subsequent fine grinding does not remove, owing,...
diamond-turned optic
Diamond turning refers to a precision machining process used to produce complex optical components, particularly lenses and...
tempered glass
A glass that is heated, then chilled (usually by an air blast) to set up internal stresses so that the surfaces are under...
fog
1. A term used to describe the clouded appearance of an incompletely polished surface that scatters light. 2. The...
screen
The large, usually flat surface onto which an image is projected for viewing. May be reflecting or transmitting (rear...
plane grating
A transmission or reflecting grating with a flat or plane surface requiring a lens or concave mirror to focus the spectrum.
differential interference contrast microscopy
Differential interference contrast (DIC) microscopy, also known as Nomarski interference contrast microscopy, is an optical...
reflectivity
The ratio of the intensity of the total radiation reflected from a surface to the total incident on that surface.
grating substrate
The substrate upon which a diffraction grating will be ruled. It must be dimensionally stable, and the surface must be...
normal
Sometimes referred to as the surface normal or 'surface norm'; the normal is an axis that forms right angles with a surface...
law of Brewster
The law stating that when light strikes a surface at such an angle that the reflected and refracted rays are perpendicular...
aspheric lens
An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical...
first-side meniscus
The process of grinding the concave surface of a single-vision spherical lens.
epitaxial equipment
Epitaxial equipment refers to a set of specialized tools and systems used in the process of epitaxy, which is the growth of...
lineament
A mappable surface feature arranged in straight or curved lines that is distinguished from surrounding surfaces and is...
blaze
1. A plane that forms one side of the groove ruled on a diffraction grating. 2. To form the individual grooves of a grating...
thermography
Thermography is a technique that involves the use of an infrared imaging device, called a thermal camera or infrared camera,...
plane wave
A wave whose surfaces of constant phase are infinite parallel planes normal to the direction of propagation.
scanning electron microscope
A scanning electron microscope (SEM) is a powerful imaging instrument used in scientific research, materials...
reflection grating
A reflection grating is an optical component that consists of a series of closely spaced, parallel reflecting surfaces or...
optical blacking
A light absorbing material applied to ground optical surfaces during the process of making that surface non reflective. Such...
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...
high
In plano work, that property of a surface determining that it is convex and contacts a flat test glass at its center.
field tilt
The angle measured between the focal surface containing the image and a plane normal to the optical axis.
double-concave lens
A diverging lens with both surfaces concave.
diffraction grating
A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel...
masks for evaporation/deposition
In the context of thin film deposition processes such as evaporation or sputtering, masks are used to selectively deposit...
protective coating
A film applied to a coated or uncoated optical surface primarily for protecting this surface from mechanical abrasion, from...
horizontal temperature gradients
Horizontal concentrations that comprise the dominant factor in atmospheric gradient correction. The range bias near due...
etching liquid
An acid used to etch the surfaces of particular materials. For glass, hydrofluoric acid is used either as a liquid or a...
rugate
Bearing alternate ridges and grooves; corrugated. Said of some optical surfaces.
mirror testing
The observation and measurement of the flatness of a mirror surface by contacting an optical flat with the mirror. The...
wedge
An optical element having plane-inclined surfaces. Usually the faces are inclined toward one another at very small angles....
Petzval surface
A paraboloidal surface on which the image is located when there is no astigmatism.
opposition effect
Also referred to as the opposition surge, the opposition effect is a photometric phenomenon in which a rough retroreflective...
wood lens
A type of radial gradient lens that can focus light even though its surfaces are flat.
etaloning
Etaloning is an optical phenomenon that occurs in imaging systems, particularly in devices such as spectrometers,...
photosensitive recording
The recording achieved when a surface, illuminated by a signal-controlled light beam, emits electrons or reacts in some...
mirror blank
A mirror blank refers to the initial piece of material from which a mirror is made. It is typically a flat or slightly...
sputtering
A vacuum deposition method in which the coating material (target) is removed from the surface of the coating source...
lenticular screen
A rear or front projection screen composed of minute optical surfaces that introduce a spread to the light beam that...
meniscus lens
A lens that has one convex surface and the other concave.
opaque projector
An opaque projector is a device used for enlarging and projecting images from opaque objects such as printed pages,...
Rayleigh scattering
Rayleigh scattering is a phenomenon that occurs when light waves interact with particles or molecules that are much smaller...
phage
A phage, short for bacteriophage, is a type of virus that infects and replicates within bacteria. Phages are composed of...
principal axis
A straight line connecting the curvature centers of the refracting lens surfaces. In a mechanical sense, a line joining the...
crush
A surface scratch or series of scratches formed by mishandling.
lens measure
A tool used to determine the curvature of a lens surface in terms of dioptric power. See lens watch; spherometer.
shallow
A term used to denote a concave surface having too long a radius of curvature. That is, its negative power is too small or...
pulse shaping
The use of variations in the power supplied to a laser to change the shape of the output pulse. The technique is used in...
polishing
The optical process, following grinding, that puts a highly finished, smooth and apparently amorphous surface on a lens or a...
surface electromagnetic waves
Waves that propagate along the interface between two different media without radiation with exponentially decaying...
direct laser interference patterning
Also called DLIP, a high-speed, high-resolution processing technique that uses high-power, pulsed laser systems to directly...
electrocapillarity modulator
A type of optical modulator with potential application in optical switching and displays, in which applied voltage causes a...
egg-crating
A weight reducing method whereby material from the rear of a reflector is removed leaving a pattern of ribs normal to the...
emissive power
The emissivity of a body times the emissive power of a blackbody at the same temperature. For a blackbody, it is the total...
internal transmittance
The ratio of the radiant power transmitted to the second surface of a medium to the corresponding radiant power that has...
Mohs hardness
Material hardness scale that is used to characterize the scratch resistance of various materials. This surface hardness...
microprojector
A miniature projecting device designed to enhance and reproduce the image generated by a smaller image-forming instrument....
underwater television system
A television system designed to obtain pictures of objects or scenes beneath the surface of the water. Generally, a...
camera tube target
The storage surface of an electron beam tube that is scanned by an electron beam to generate an output-signal current...
ultramicrophotography
The process of microphotography that involves the reduction of the original at a ratio greater than 100 to 1. The process is...
photoelectric effect
The emission of an electron from a surface that occurs when a photon impinges upon the surface and is absorbed. This effect...
interferometer
An instrument that employs the interference of lightwaves to measure the accuracy of optical surfaces; it can measure a...
perfect diffuser
A surface that obeys Lambert's cosine law and has a reflectance of unity.
MSM photodiode
A metal-semiconductor-metal (MSM) photodiode is a type of photodetector that consists of metal electrodes on a semiconductor...
illuminance
Luminous flux incident per unit area of a surface; luminous incidence. (The use of the term "illumination" for...
augmented reality
Augmented reality (AR) is a technology that integrates digital information, typically in the form of computer-generated...
transient calorimetric technique
A method of measuring total hemispherical emissivity of the plane surface of a solid that consists of thermally isolating a...
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...
isophote
A curve or surface having equivalent light intensity.
Young's construction
A method of graphical ray tracing through a boundary surface dividing two media of differing indices of refraction.
photonic crystal surface-emitting laser
A photonic crystal surface-emitting laser (PCSEL) refers to a type of laser diode that emits light from its surface rather...
scanning coherent slope microscopy
Measures by heterodyning interferometry the local slope of a vibrating sample. The method allows the reconstruction of a...
antireflection coating
An antireflection coating (AR coating) is a thin film or coating applied to optical surfaces, such as lenses or windows, to...
dig
A cosmetic defect on the surface of an optical element. A dig is nearly equal in terms of its length and width. The size is...
epitaxial deposition
Epitaxial deposition is a process used in semiconductor manufacturing and materials science to grow a thin crystalline...
coverslip
A coverslip, also known as a cover glass or cover slip, is a thin and flat piece of transparent material typically made of...
polished mold
A mold for glass or plastics often made of stainless steel to prevent pitting or oxidation in service. It is polished to the...
diffractive optics
Optical elements that use diffraction to control wavefronts. Diffractive optical elements include diffraction gratings,...
image distance
The distance from the last surface of a lens system to the image. For a thin lens system, this distance is equivalent to the...
laser damage
A natural or mechanical system adversely affected by the influence of laser radiation. During laser damage the common effect...
adsorption
The process by which a substance, usually a solid, attracts and retains on its surface the molecules of another substance.
photosurface
The surface from which electrons are ejected by the incidence and absorption of photons.
retroreflector
A retroreflector is an optical device or structure that reflects incident light or electromagnetic waves back to their...
spatter
Of evaporative coatings, a condition resulting when small chunks of material fly from the hot crucible onto the substrate...
incident ray
A ray of light that falls upon or strikes a surface of an object such as a lens. It is said to be incident to the surface.
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...
profilometry
Measurement of surface roughness or quality through the use of a diamond-pointed stylus connected to a coil in an electric...
centered curve
The surface curvature designed to reduce the marginal error found in the periphery of a spectacle lens.
flat machine
A polishing machine designed to permit adjustment of the polisher speed and motion for the control of flat surfaces.
scattering
Change of the spatial distribution of a beam of radiation when it interacts with a surface or a heterogeneous medium, in...
turbidity
Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These...
off-axis paraboloid and ellipsoid mirror
Off-axis paraboloid and ellipsoid mirrors are specialized optical components used in various optical systems, particularly...
scatterometer
An instrument used to determine the absolute or relative scatter levels of optical surfaces.
superreflector
A reflector having a surface that has been superpolished to reduce residual sleeks and scratches and microroughness so that...
simultaneous exposure and development
The process, used with a positive photoresist, in which the photoresist is immersed in developing chemicals while being...
scatterplate
A flat plate having its surface formed into a random pattern by abrasives. Radiation wavelengths that are longer than the...
null lens
A lens used in the optical testing of an aspheric surface. It converts a spherical wavefront into one that precisely matches...
cylinder axis
In a cylindrical lens, the meridian parallel to the generating lines of the cylindrical surface. In a toric lens, the...
lambertian surface
A perfectly diffusing surface; the intensity of the light emanating in a given direction from any small surface component is...
microchannel plate
A microchannel plate (MCP) is a specialized electron multiplier device used in various applications such as particle...
metalens
A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light...
hydroscopic
Designed to observe objects below the surface of water. Not to be confused with hygroscopic.
component
1. A constituent part. It may consist of two or more parts cemented together, or with near and approximately matching...
aspheric lens system
An optical system having one or more lens or mirror components that have nonspherical surfaces. These surfaces, whether...
Polarization Imaging
A subsurface imaging technique based upon the polarization of light reflected off an object. The polarization of reflected...
eye relief
Also termed eye distance. The distance between the vertex of the last optical surface of a visual optical system and the...
custom lapping and polishing services
Custom lapping and polishing services involve specialized processes used to improve the surface finish and dimensional...
figuring
The process whereby the shape of an optical surface is altered by polishing.
lateral shearing interferometer
A lateral shearing interferometer is an optical device used in interferometry to measure phase differences between two beams...
metallic coating
A thin layer of metal deposited on the surface of a substrate. The film may serve as a reflector, beamsplitter, neutral...
optical data storage
The storage of information via optical means, primarily employing a low-power laser to inscribe data on a photosensitive...
pushbroom scanning
Pushbroom scanning is a technique used in remote sensing and imaging systems, particularly in satellite and aerial sensors,...
fire cracks
Small clefts or fissures that penetrate the glass surface in the form of short-hooked crescents. Fire cracks result from a...
surface reflection
Also known as Fresnel reflection. That portion of the incident radiation that is reflected from the surface of a refractive...
aluminizing
The process of applying a film of aluminum to a surface, usually by evaporation in a vacuum.
photomultiplier tube
A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely...
Fabry-Perot interferometer
A multiple-beam interferometer, usually consisting of two flat plates, with high reflective ability. The plates are set...
liquid gate
An immersion liquid used to treat polarizing filters to eliminate the effects of surface variations and to minimize the...
optical waveguide
Any structure having the ability to guide the flow of radiant energy along a path parallel to its axis and to contain the...
metallographic microscope
A specially designed microscope for observing the etched surface of a polished metal specimen. The specimen is often laid...
momentum transfer
In physics, momentum transfer is the amount of momentum transferred from one particle to another during particle collision...
aplanatic surface
An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and...
focusing corner cube
A retroreflector that can focus a beam of light, with one planar reflective surface, one spherical and a third that is...
scanning electron microscopy
Scanning electron microscopy (SEM) is an advanced imaging technique used in microscopy to obtain high-resolution,...
radiation pressure
The force exerted on a surface by radiation.
machine vision lighting
Machine vision lighting refers to the use of specific lighting techniques and equipment in the field of machine vision,...
liquid crystal on silicon
Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based...
electrochromic display
Type of solid-state display tube in which the readout surface is coated with a material that changes color when positively...
anamorphic lens
A lens, usually having one or more cylindrical surfaces, used to produce distorted images and later to restore them to true...
converging meniscus
A converging lens with one convex and one concave surface.
mirror mount
A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are...
liquid-surface holography
The acoustical holographic process in which the hologram consists of slight elevations in a liquid surface, in the areas of...
magnetic disc
A plastic disc coated with ferric oxide or other films on which data can be stored by selectively magnetizing areas of the...
principal plane
In a lens or lens system, that surface at which the projections of an entering and exiting ray intersect. Also known as the...
service-mount device
A surface-mount device (SMD) is an electronic component that is mounted directly onto the surface of a printed circuit board...
free-spectral range
The frequency space between consecutive transmission peaks in the transmission spectrum of a Fabry-Perot interferometer or...
image intensifier
An image intensifier, also known as an image intensification tube or image intensification device, is a specialized...
catoptric system
An optical system in which the only image-forming elements are curved-surface mirrors; e.g., a Cassegrain lens system.
fiber undercut
The distance between the surface of a ferrule and the surface of a fiber end, provided that the ferrule extends above the...
ion-beam sputtering
Ion-beam sputtering (IBS) is a physical vapor deposition (PVD) technique used for depositing thin films onto substrates. It...
ocular accommodation
The physical adaption of the eye lens, by means of ciliary muscle contraction, in order to maintain a clear, in focus image...
modified chemical vapor deposition
Modified chemical vapor deposition (MCVD) is a technique used in the fabrication of optical fibers. It is a specialized form...
attenuated total reflectance spectroscopy
Attenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain IR spectra of samples....
zones
1. In a polished surface, concentric waves that appear as zones in Newton's rings when a test glass is applied. 2. An...
microlithography
A technique for producing micron-size structures on surfaces by using short-wavelength light or electron beams.
attosecond-pump attosecond-probe spectroscopy
Attosecond-pump attosecond-probe spectroscopy (APAP) is an advanced technique in ultrafast spectroscopy that allows...
illumination distribution
Generally, the orientation of rays of light striking a surface.
cosine collector
Translucent collector developed to compensate for the partial blocking of a flat surface's collection angle that normally...
etalon
An etalon is an optical device that consists of two parallel reflecting surfaces separated by a precise and known distance....
GRIN lens
A GRIN (gradient index) lens is a type of optical lens that utilizes a gradient in refractive index across its volume rather...
semifinished blank
A formed piece of glass, one surface of which has been ground and polished to the required curvatures.
planoconvex lens
A lens that has one plane surface and one convex surface.
optical artifacts
Optical artifacts refer to undesired or unintended effects that can occur in optical systems, such as microscopes, cameras,...
coring
A mass-relieving method whereby material is removed through the sides of a reflector in a direction parallel to the surface....
test cube
A device used to detect elevation, pyramid and resolution errors in prisms and other components by bringing them into...
grazing incidence
Light striking a surface at an angle almost perpendicular to the normal.
2D profile sensor
A 2D profile sensor is a type of sensor used in various industrial and technological applications to measure and capture...
convex
Convex is an adjective used to describe a surface or shape that curves outward, bulges, or has a rounded and outwardly...
reflected ray
The light ray leaving a reflecting surface, indicating the path of light after reflection.
femtosecond laser
A femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds,...
remote sensing
Remote sensing is a method of data collection and observation where information about objects, areas, or phenomena on...
triple mirror
Also known as corner-cube reflector or retrodirective reflector. Three reflecting surfaces, perpendicular to each other,...
mode hopping
Mode hopping in the context of lasers refers to a phenomenon where a laser system abruptly switches from one longitudinal...
Langmuir-Blodgett technique
A method of depositing crystalline films one molecular layer at a time, by dipping the substrate into water containing a...
reflective
The term reflective is an adjective that describes the ability of a surface or material to reflect light or other forms of...
diffuse reflector
A reflecting surface that scatters radiation that is incident on it, thus producing diffuse reflection.
flow channel
In various fields such as fluid dynamics, microfluidics, and biotechnology, a flow channel refers to a defined pathway...
vertical external cavity surface-emitting laser
A laser that has a surface-emitting semiconductor gain element coupled to an external mirror designed to complete the laser...
volume Bragg gratings
Volume Bragg gratings (VBGs) are specialized optical elements that consist of periodic variations in refractive index...
freeform mirrors
Freeform mirrors refer to reflective optical components that deviate from traditional symmetric or rotationally symmetric...
deflection under static load
For an optical table, the amount of displacement that occurs when a heavy load is placed or moved on the surface. To measure...
functional near-infrared spectroscopy
Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin...
case hardening
A surface heat-treating process that produces a highly stressed surface. In case-hardening of glass, a plate of glass is...
patina
A thin film or coating that forms on various finished surfaces. On optical surfaces it usually denotes aging.
autostigmatic microscope
A microscope to which a beamsplitter and illuminated reticle have been added to measure the radius of curvature of a...
photoelectric reflectometer
A photoelectric photometer used to measure the reflectance of a surface.
bakeout
The elimination of gases from the surfaces of a vacuum system by heating the surfaces when the pumping phase is occurring.
Fizeau fringes
Fizeau fringes are interference fringes observed in an interferometer, specifically in a Fizeau interferometer. The Fizeau...
diffuser
An optical diffuser is an optical component or material designed to scatter or diffuse light that passes through it. It is...
surface
1. In optics, one of the exterior faces of an optical element. 2. The process of grinding or generating the face of an...
aerial mapping
The use of photographs taken from the air to construct graphic maps and charts of ground surfaces.
open bubble
A bubble at a polished surface that has been opened by grinding or polishing.
field emission microscope
An image-forming instrument in which a strong electrostatic field causes cold emission of electrons from a sharply rounded...
face-pumped laser
A device in which slab geometry internally compensates for thermal-optic distortion; the solid host material -- glass or...
infrared radiation source
Any object that emits radiation of a wavelength lying between about 0.75 to 1000 µm. A calibrated secondary source...
abrasive
Powder used to produce a smooth optical surface through abrasive polishing. Compounds may produce a surface finish specified...
first-side toric
The process of grinding the toric surface of a single vision sphero-cylindrical lens.
physisorption
A type of adsorption in which the adsorbed layer is attached to the adsorbent surface by an attractive force between the...
fluorescent screen
A fluorescent screen refers to a phosphorescent or fluorescent-coated surface that emits visible light when exposed to other...
photolithography
Photolithography is a key process in the manufacturing of semiconductor devices, integrated circuits, and...
external photoelectric effect
The ejection of electrons from the surface of a solid by the absorption of a sufficient amount of photons.
radial gradient
In gradient index optics, a gradient profile in which the index varies in a direction perpendicular to the optical axis....
phase screen
A phase screen, in the context of optics and wave optics, refers to a surface or medium that introduces a phase delay to an...
slab-off
The process of making an abrupt break in a spherical surface on a spectacle lens so that a new center of curvature is set...
whispering gallery mode
Whispering gallery mode (WGM) refers to a phenomenon in wave physics, particularly in optics, where waves, such as light or...
optical figure
The amount by which an optical surface deviates from its ideal design value, expressed in wavelengths of light. Optical...
surface plate
A large table with an accurately designed plane surface used to test other surfaces, or to provide a true surface for...
reference surface
The surface of an optical fiber that is used as a reference when joining optical fibers. Although the outermost cladding is...
flat blank
A piece of glass having a crude plano surface on each side.
phase-change optical disc
An erasable data recording and storage medium that uses a laser to heat the crystalline surface of the disc to a certain...
luminance
Luminous flux emitted from a surface per unit solid angle per unit of area, projected onto a plane normal to the direction...
assist gas
A gas, such as oxygen, that improves the speed and efficiency of a laser cutter or welder when applied to the work surface,...
scattered light filter
A specific type of filter designed to reduce the amount of light scattered by reflections from the edges of optical...
lens testing equipment
Lens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance,...
photoresponse nonuniformity
Noise created by patterns imaged on a CCD surface. Pixel sensitivity is altered by responsivity during illumination.
sputtering equipment
Sputtering equipment is machinery used in the process of physical vapor deposition (PVD), specifically sputtering....
Ultraviolet-C
Ultraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible...
ultrasonic cleaning equipment
Ultrasound used in the cleaning of metal and optical parts by virtue of its vibration rates. Large acoustic forces break off...
micromanipulator
A device that provides means for accurately moving minuscule tools over the surface of a microscopic object. The motion...
absorption lens
An optical lens manufactured to control the transmission of light over a specified wavelength range. Low absorption lenses...
front-surface mirror
An optical reflector with the reflective coating applied to the front surface of the substrate. This eliminates the ghost...
surface quality
The specification of allowable flaws in a surface by comparison to reference standards of quality. Two graded sets of...
toric surface
A surface that is swept out by revolving a circle about an axis that lies in the plane of the circle but that does not...
angle of incidence
The angle formed between a ray of light striking a surface and the normal to that surface at the point of incidence.
acoustic surface wave
 prism apex
The thin edge of a refracting prism; the line of intersection of two refracting surfaces of a prism.
mirror
A smooth, highly polished surface, for reflecting light, that may be plane or curved if wanting to focus and or magnify the...
covered groove
A technique used in integrated optics where a groove is cut on a substrate surface and covered by a thin film to facilitate...
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...
ultrasonic
Ultrasonic refers to sound waves with frequencies higher than the upper audible limit of human hearing, typically above...
surface normal
 diffuse reflectance spectroscopy
Diffuse reflectance spectroscopy (DRS) is a nondestructive analytical technique used to investigate the optical properties...
molded blank
A blank whose basic surface curves are attained by heating and forming a given weight of raw glass; a rough glass blank...
prism
A prism is a geometric optical element with flat, polished surfaces that refract light. It is typically a solid, transparent...
flare
Nonimage-forming light, concentrated or diffuse, that is transmitted through the lens to the image. It is frequently the...
plane
A surface that has no curvature; a surface that is perfectly flat.
hackle
A defect in the cleaved end face of an optical fiber, defined as multiple surface irregularities across the fiber surface. A...
window
1. A piece of glass with plane parallel surfaces used to admit light into an optical system and to exclude dirt and...
saddle
A term used to describe a saddle-shaped -- i.e., convex along one axis, concave along the other -- polished surface,...
spectral signature
A spectral signature, in the context of remote sensing and spectroscopy, refers to the unique pattern or characteristic...
ordinary ray
The ray that has an isotropic speed and maintains a uniform polarization in all propagation directions when traveling in a...
darkening
The formation of a dark-colored film on a metal surface by chemical activity.
heat sink
A series of flanges or other conducting surfaces, usually metal, attached to an electronic device to transmit and dissipate...
Rayleigh limit
The restriction of wavefront error to within a quarter of a wavelength of a true spherical surface to assure essentially...
spatial resolution
Spatial resolution refers to the level of detail or granularity in an image or a spatial dataset. It is a measure of the...
bring-in
The final correction of a polished surface or of an angle to the specified precision.
clear eye distance
In a visual optical system, the axial distance from the last mechanical surface of the eyepiece to the exit pupil.
scratch
A defect on a polished optical surface whose length is many times its width. Block reek is a chainlike scratch formed in...
etching
The engraving of a surface by acid, acid fumes or a tool; a process extensively used in the manufacture of reticles.
ray tracing
Ray tracing is a rendering technique used in computer graphics to simulate the way light interacts with objects in a scene....
magnetic bubble film
An amorphous film in which cylindrical bubbles of reverse magnetization can be formed to follow circuit paths usually made...
optical surface
A reflecting or refracting surface contained within an optical system.
diamond turning
Diamond turning, also known as diamond machining or diamond cutting, is a precision machining process used to produce...
Schlieren photomicrography
The photomicrographic recording of Schlieren effects, irregular refractions of light from optic surfaces or areas of thin,...
normal congruence
Condition in which a perpendicular surface can be discovered for every ray in a group. This condition is commonly observed...
infrared camera
An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the...
Coulomb damping
Conversion of vibratory energy into heat that is observed in the rubbing of two dry surfaces over each other.
planoconcave lens
A lens with one plane surface and one concave surface.
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...
optical disc
A rigid medium, generally a polycarbonate substrate coated with a reflective aluminum layer, that stores information (such...
doublet
1. A compound lens consisting of two elements. If there is an air space between the elements it is called an...
linear positioning stage
A linear positioning stage, also known as a linear stage or translation stage, is a precision mechanical device used to...
zeta particle
The difference in electrokinetic potential between the stationary liquid connected to a solid phase surface and the mobile...
projection thermography
The measurement of surface temperature by a thermograph that forms a pattern of the heat radiated by the surface on a...
aspherizing
The modification of the spherical surfaces in an optical system to correct for spherical aberration.
Hindle sphere
A null optic in the form of a concave spherical mirror; used for the test and evaluation of a hyperboloidal aspheric surface.
flatbed scanner
An imaging device analogous to a drum scanner, but operating at greater speeds; it uses a row of sensors to traverse an...
stick machine
A polishing machine with a lens mounted on a wooden stick, allowing a very wide sweep. It is used to polish hemispherical or...
backscatter
Backscatter refers to the phenomenon in which radiation or waves are scattered backward, opposite to the direction of the...
antifog coating
A coating that is capable of stopping the condensation of moisture on an optical surface.
solar constant of radiation
Solar radiation intensity existing in free space at the mean solar distance of the Earth. Commonly expressed in g cal...
infrared vidicon
A vidicon that has a photoconductive surface that can be excited by infrared radiation.
photorefractive keratectomy
A surgical procedure for correcting vision by reshaping the outer surface of the cornea through the use of a laser system.
metallographic polishing machine
A small optical polishing machine intended for polishing the surface of a metal specimen before etching for examination...
illuminated
Characteristic of a surface or object that has luminous flux incident upon it.
chemisorption
The binding of gas to a surface or in matter by chemical activity.
reflection reduction coating
The thin, transparent film made up of specific substances applied to glass-air surfaces for the purpose of decreasing the...
silver spots
Spots in a polished glass surface that are opaque and have a silvery, metallic reflection.
Littrow spectrograph
A spectrograph using a prism that has an internally reflecting surface and that serves as a constant deviation prism.
iridescence
The rainbow exhibition of colors, usually caused by interference of light of different wavelengths reflected from...
test glass
A transparent block shaped accurately to reverse curvatures of the components it is used to test. By contacting an...
texel
A contraction for "texture element." A base unit used in computer graphics that defines the surface of three-dimensional...
pyramid error
Pyramid error in optics refers to an aberration in the shape of an optical surface, particularly in the context of mirrors....
ultraviolet microscopy
The study and photographing of microscope specimens in ultraviolet light; using an optical microscope containing fluorite...
aspheric
Not spherical; an optical element having one or more surfaces that are not spherical. The spherical surface of a lens may be...
autocollimator
An autocollimator is an optical instrument used for measuring small angular deviations with high precision. It operates on...
halation
1. In a cathode-ray tube, the glow surrounding a bright spot that appears on the fluorescent screen as the result of the...
monostable display
A matrix-controlled display that has no information storage at the display surface.
ripples
The approximately concentric waves that form on a surface that has been polished without an oscillation of the polishing lap.
photochemical hole burning
A method of producing disks for erasable optical data storage. Information is recorded by a laser beam that generates pits...
compound lens
A lens composed of two or more separate elements of optical glass that may or may not be cemented together. The surfaces of...
blackbody source
A blackbody source, often simply referred to as a blackbody, is a theoretical or practical physical object that absorbs all...
spherical aberration
Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface...
wavefront
In considering a field of electromagnetic energy emanating from a source, the wavefront is a surface connecting all field...
lenticular
An array or mosaic of optical surfaces. May be a number of lenses closely packed to form multiple images or many parallel...
exitance
Flux leaving a surface per unit area.
videodisc
A disc whose surface contains recorded digital data at high-packing densities arranged in concentric rings. The data,...
laser texturing
Laser texturing is a manufacturing process that involves using a laser beam to selectively modify the surface of a material,...
incidence
Flux incident per unit area of a surface.
toric lens
A lens having one or more toric surfaces. A toric surface is one having a maximum power in one meridian and a minimum power...
divergent-meniscus lens
A lens with one surface convex and the other concave, the latter having the greater curvature. It also is known as a...
fiber optic field flattener
A plate consisting of fused optical fibers with both surfaces ground and polished, and having the entrance surface curved to...
optical instrument dome
A dome-shaped structure used for some optical instruments in place of a flat window. The transparent material should be of...
optical glass
Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems,...
aplanatic points
Aplanatic points refer to specific points in an optical system where certain aberrations, such as spherical aberration or...
low
Term used to describe an optical surface that contacts the test glass only at its edges.
Secondary Speckle Pattern
A self-interference effect that generates random patterns; secondary speckle pattern (SSP) typically occurs in diffuse...
conical lens
A lens with a surface that is a cone instead of the usual sphere.
light pattern
In optics, a pattern, such as the Buchmann-Meyer pattern, that may be viewed when the record surface is illuminated by a...
electron storage ring
An advanced magnetic device used in x-ray lithography to beam x-rays onto the surface of silicon wafers used for...
sagged bevel
The shape of the edge of a concave surface when the depth of the bevel plane to the vertex of the surface is controlled to a...
interferometric modulator display
Interferometric modulator display (IMOD) is a type of display technology used in electronic devices, known for its energy...
pitch polishing compound
Pitch for polishing mixed with other materials to give it the right viscosity so that it will follow the fine-ground lens...
luminous exitance
The total luminous flux given out per unit area; i.e., the sum of the luminous emittance and any radiation that is reflected...
label-free
Label-free refers to a technique or method that does not require the use of additional labels, tags, or markers to detect or...
front vertex focal distance
The distance between the front focal point and the vertex of the front surface.
fold
1. A flaw in a blank caused by folding the blank's surface during its formation. 2. The change in the direction of a...
second-side toric
The process of grinding the concave surface of a sphero-cylindrical lens.
steradian
The unit solid angle subtended at the center of a sphere by an area on its surface equivalent to the square of the radius;...
glass
A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or...
photodischarge spectroscopy
A spectroscopic process that detects and analyzes the discharge from an extrinsic surface with less than bandgap light. This...
marginal error
The distortion in an ophthalmic lens resulting from the refraction of light rays entering the periphery of the lens surface....
hyperspectral resolution
Hyperspectral resolution refers to the level of detail or granularity in the spectral information captured by a...
cosine law of illumination
Law relating the illuminance (or irradiance) of a surface to the cosine of the angle, q, between the normal to the surface...
chemical vapor deposition equipment
Chemical vapor deposition (CVD) equipment refers to a class of specialized apparatus used in the process of chemical vapor...
surface analysis by laser ionization
(SALI) A type of spectroscopy in which neutral atoms or molecules are ionized by an excimer laser beam and then measured by...
sharp
A term used to describe a convex surface having too short a radius of curvature. To correct this condition, material is cut...
gravimeter
An instrument capable of precise measurements of the Earth's gravity. This permits the detection of small changes in local...
normal incidence
Light striking a surface at an angle perpendicular to the surface.
acetone
Optic surface cleaning liquid that may be applied to glass, crystal, dielectric and metal surfaces; however, may not be...
Littrow prism
A 30-60-90° spectrograph prism that is coated on the surface opposite the 60° angle with a reflecting film.
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...
internal surface
A nonoptical surface, within lenses and lens mounts, that contributes largely to flare by reflecting light into the image...
internal
With reference to absorbance, absorptance, transmittance and the like, the processes occurring within a specimen between the...
Airy differential equation
The equation devised by Sir G.B. Airy for the analysis of light diffraction near a caustic surface: (d2f/dz2) - zf = 0 where...
virtual retinal display
The use of miniature scanners to project raster-scanned video images directly onto the surface of the human retina,...
polishing jig
In fiber optics, a device used to polish a biconic plug to a specified length and surface finish. Also called a polishing...
vertical leveling mirror
A two-sided mirror suspended by a pendulum mechanism. An autocollimator set normal to such a mirror surface will, by...
cornea
The transparent front layer of the eye. Light entering the eye is refracted (converged) by the outer surface of the cornea.
computer-generated hologram
A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than...
concave and convex spherical mirror
Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These...
irradiance
Radiant flux incident per unit area of a surface. Also called radiant flux density.
surface quality standards
The standards of MIL-O-13830 set by the US government relative to tolerable surface scratches and other such defects in an...
facet
1. One of the plane-reflecting surfaces on a multisurfaced polygon. 2. The cleaved end mirror of a laser diode's active...
topological photonics
Topological photonics is a branch of physics and optics that explores the application of topological concepts to the...
freeform optics
Freeform optics refers to the design and fabrication of optical surfaces that do not follow traditional symmetric shapes,...
magnetorheological finishing
Magnetorheological finishing (MRF) is a precision optics polishing technique used for shaping and finishing optical surfaces...
fused array of fibers
Optical fibers fused together to form a solid, vacuum-tight assembly in the form of a slab or rod. Discs or rectangular...
oil-on plate
A polished plano-parallel plate that is contacted to an unpolished glass surface to permit see-through analysis of the...
flying spot scanner
A device used to scan, with a small, intensely bright spot, portions of a picture surface and to transform the original...
generating
A rapid roughing process for the quick removal of glass, the first step in manufacture of a curved lens surface. It is...
axial gradient technology
A method of designing lasers whereby the laser rod is cut into elliptical discs and cooled by running water over the disc...
optical work
The degree to which the surface of a lens causes an incident ray of light to bend, or the amount of convergence or...
dark-field microscopy
A technique whereby the sample is illuminated by a hollow cone of light larger than the acceptance angle of the objective,...
oleophobic
Oleophobic is a term used to describe substances or materials that repel or resist oils. The word oleophobic comes from the...
autocollimation
Technique of projecting an illuminated target at infinity and receiving the target image after reflection from a flat mirror...
scanning acoustic microscope
Also called scanning laser acoustic microscope. A device that uses high-frequency ultrasound waves to penetrate surfaces. A...
fringes of superposition
The multiple beam form of Brewster's fringes formed when the two plane-parallel plates have high-reflecting surfaces.
optical flat
A piece of glass, pyrex or quartz having one or both surfaces carefully ground and polished plano, generally flat to less...
Nomarski microscopy
Also referred to as differential interference contrast (DIC) microscopy; Nomarski microscopy is a unique form of microscopy...

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