PowerPhotonic Ltd. - Bessel Beam Generator LB 6/24

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HIWIN Corp. - Linear Motor Stages MR 6/24

Videology Industrial-Grade Cameras - Mini Color Camera 2024 HP

55 terms

Photonics Dictionary: V

Clear All Filters x Ni x V x
variable-speed scanning

A scanning technique in which the optical density of the film being scanned controls the speed of deflection of the scanning beam.

vernier acuity

The degree to which a pair of fine lines can be aligned to each other. A normal observer will demonstrate an accuracy of 10 arc seconds and a repeatability of 5 arc seconds.

vernier interferometer

A phase-shift interferometer used to detect the relative angular speeds or positions of two concentric rotors.

vibronic transition

A type of change in the energy levels of molecules in a laser that results in lasing action. Vibronic transitions are those between one electronic level and another.

V-number -> normalized frequency

Also referred to as the V number in fiber optics; the normalized frequency is a dimensionless quantity, denoted by the symbol V, given by: where a is waveguide core radius, l is wavelength in vacuum,...

vacancy

In an ionic crystal, the region in the crystal lattice where the ion, predicted to be present, is absent.

vacuum

In optics, the term vacuum typically refers to a space devoid of matter, including air and other gases. However, in practical terms, achieving a perfect vacuum, where there is absolutely no matter...

vacuum chamber

A vacuum chamber is a sealed enclosure from which air and other gases are removed to create a low-pressure environment, typically close to or at a complete vacuum. These chambers are often...

vacuum gauge

A gauge designed to measure the degree of vacuum in an evacuated vessel. A simple U-tube containing mercury is adequate for low vacua, but for high vacua other methods must be employed. See McLeod...

vacuum phototube

A phototube that functions within a vacuum and thus eliminates the effects of gaseous ionization on its electrical properties.

vacuum spectrography

The technique of producing spectrograms in wavelengths beyond 120 nm by the use of a diffraction grating and a Schumann plate in a vacuum environment.

vacuum ultraviolet spectroscopy

A method of spectral analysis using wavelengths between 100 and 300 nm that utilizes both emission and absorption techniques.

Van der Waals

Van der Waals forces refer to the attractive or repulsive forces between molecules (or parts of molecules) that arise from fluctuations in electron distribution. These forces are relatively weak...

vanadate laser

Lasers based on neodymium-doped yttrium or gadolinium vanadate crystals. These include yttrium vanadate (Nd:YVO4), gadolinium vanadate (Nd:GdVO4), and lutetium vanadate (Nd:LuVO4). Vanadate lasers...

vapor degreasing

A method of cleaning and drying coated optical components. The cooled parts are placed in a container above a boiling solvent, whose vapors condense on the parts. When the parts reach the temperature...

vapor-phase epitaxy -> epitaxy

A well controlled thin films technique for growing films with good crystal structure in ultra high vacuum environments at very low deposition rates. Epitaxy methods are well known for the growing of...

variable-focus condenser

An Abbe condenser in which the upper lens element is fixed. The lower lens may focus the illumination between the elements so that it emerges from the fixed lens as a large-diameter parallel bundle....

variable-focus lens

A lens assembly containing several movable elements to permit changing of the effective focal length (EFL). Unlike a zoom lens, a variable-focus lens may require refocusing with each change of EFL....

varifocal -> variable-focus lens

VCSEL

vertical-cavity surface-emitting laser

VDM

vapor density monitoring

VDU

video display unit

vector correlation

A machine vision technique of image correlation whereby the correlation kernel (template of the desired image) is transformed into a group of vectors, each representing a specific feature of the...

Vegard-Kaplan bands

The bands found by Vegard in the spectrum of the aurora borealis and by Kaplan in the nitrogen afterglow. They are formed by the effect of metastable nitrogen molecules.

Verdet constant

A factor of an equation of the Faraday effect, which is the rotation of the plane of light polarization by transparent materials in a magnetic field. Therefore, in the equation: where a...

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 resonator. VECSELs can be electrically or optically pumped. The extended...

vertical leveling mirror

A two-sided mirror suspended by a pendulum mechanism. An autocollimator set normal to such a mirror surface will, by definition, have its optical axis set horizontal.

vertical resolution

In television system specifications, the number of parallel horizontal black and white lines of equal thickness, that can be resolved from top to bottom of the raster. (One line equals either a black...

vertical retrace

With respect to television, the returning direction of the electron beam during the vertical blanking period.

vertical-cavity laser diode

A type of surface-emitting laser diode that uses dielectric mirrors to produce surface emission. The laser cavity is established in a vertical direction with respect to the plane of the active region.

vertical-cavity surface-emitting laser -> vertical-cavity laser diode

very long baseline interferometry

Consists of a pair of radio telescopes concentrated on a single celestial object. This technique creates a single radio telescope with a diameter equal to the distance between the pair, which allows...

vibrational circular dichroism

Vibrational circular dichroism (VCD) is a spectroscopic technique used to probe the chiral properties of molecules. It measures differences in the absorption of left- and right-circularly polarized...

vibrational transition

A vibrational transition refers to a change in the vibrational energy of a molecule. Molecules consist of atoms that are connected by chemical bonds, and these atoms are not stationary but are in...

video

Referring to the bandwidth and spectrum location of the signal produced by television or radar scanning.

video detector

A device, such as a thermionic or crystal diode, that is introduced into the vision channel of a television receiver to select the signal from the intermediate-frequency carrier.

videography

Videography refers to the process of capturing moving images and recording them in a digital format. It involves the use of video cameras, lighting equipment, and audio recording devices to create...

vidicon

A small television tube originally developed for closed-circuit television. It is about 1 inch in diameter and 5 inches long. Its controls are relatively simple and can be operated by unskilled...

view camera

A camera that permits adjustments in the perspective of an image; this is accomplished by the camera design, which permits tilt, swing, rise or fall of the image transmitted. Also known as a...

viewfinder

A device, optical or electronic, that may be joined to a camera so that the operator may perceive the scene as the camera does.

vignetting

In an optical system, the gradual reduction of image illuminance as the off-axis angle increases, resulting from limitations of the clear apertures of elements within the system.

virtual base

The product of the actual base or baseline of a rangefinder or heightfinder, and the power or magnification of the instrument.

virtual histology

Virtual histology refers to the use of digital technology and computational methods to simulate or recreate histological images and structures without the need for traditional physical slides and...

virtual reality

Virtual reality (VR) is a computer-generated simulation of a three-dimensional environment or experience that can be interacted with and explored by an individual using electronic devices, such as a...

virtual retinal display

The use of miniature scanners to project raster-scanned video images directly onto the surface of the human retina, eliminating the need for a projection surface.

visible

That term pertaining to the spectral region that can be perceived by the eye.

visual acuity

The numerical definition of the ability of an observer to perceive fine detail. The average value may be taken as one minute, or 6.7 cycles/mm, at 250 mm (normal viewing distance).

visual storage tube

An electron tube that stores and visually displays information by means of a cathode-ray-beam-scanning and charge-storage mechanism.

visually coupled airborne systems simulator

A visual system including a tiny television tube and imaging optics, all contained in a helmet to be worn by pilots in flight simulator training.

void

A blank area (caused by insufficient inking of the paper) that falls within the range of an intended character stroke in an optical character-recognition system.

Photonics DictionaryV