Bristol Instruments, Inc. - 872 Series High-Res 4/24 LB

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Photonics Dictionary

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transversely excited atmosphere carbon dioxide laser

Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The electrical excitation pulse occurs transversely to the optical axis...

transversely excited atmosphere laser

Also known as TEA laser. A coherent optical source with a wide wavelength range in the infrared, visible and ultraviolet that uses an electrical discharge transverse to (across) the optical axis to...

traveling wave phototube

A traveling wave tube (TWT) containing a photocathode and window that, receiving a laser beam, produces a modified photoelectric current that is accelerated and propagated into its helical frame.

trial sets (ophthalmic)

Sets of lenses (positive, negative and cylindrical) usually mounted in circular rims suitable for slipping into trial spectacle frames. The individual lenses bear codes that state their power in...

triple aplanat

A compound lens consisting of two negative lenses of flint glass. A double-convex lens of crown glass is cemented between the two negative lenses. With this system, it is possible to decrease...

tristimulus colorimeter -> colorimeter

A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides objective and standardized color information, typically expressed in terms...

tungsten diselenide

Tungsten diselenide (WSe2) is a member of the transition metal dichalcogenides (TMDs) family, composed of tungsten (W) and selenium (Se). Similar to other TMDs, tungsten diselenide possesses a...

tunneling

An observed effect of the ability of certain atomic particles to pass through a barrier that they cannot pass over because of the required energy level, based on a law of quantum mechanics that...

turbidity

Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These particles can include sediment, silt, clay, plankton, and other microscopic...

turbulence propagation medium

Simulation of atmospheric turbulence for laboratory experimentation purposes, achieved by creating an unstable vertical gradient temperature in a tank filled with water.

twinning

A defect of natural quartz crystals in which both the right and left quartz are in the same crystal.

twisted intramolecular charge transfer

Twisted intramolecular charge transfer (TICT) is a phenomenon observed in certain organic molecules containing electron-donor and electron-acceptor groups that are linked together within the same...

ultramicrophotography

The process of microphotography that involves the reduction of the original at a ratio greater than 100 to 1. The process is usually accomplished by the use of a reduced-scale negative, which, in...

ultramicroscope

A dark-field microscope used to view extremely small objects. These objects are suspended in a gas or liquid in an enclosure having a black background. A convergent pencil of bright light enters from...

ultrasonic cross grating

A two- or three-dimensional space grating formed when ultrasonic beams with varied paths of propagation intersect.

ultrasonic

Ultrasonic refers to sound waves with frequencies higher than the upper audible limit of human hearing, typically above 20,000 Hz. These waves are termed ultrasonic because they are beyond the range...

Ultraviolet-C

Ultraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible light. UV-C radiation spans the electromagnetic spectrum with wavelengths...

ultraviolet reflectance

Ultraviolet reflectance refers to the ability of a material or surface to reflect UV light. Ultraviolet light is electromagnetic radiation with wavelengths shorter than those of visible light,...

ultraviolet-visible spectrometer

Also known as UV-VIS spectrometer, a device that measures the absorbance, reflectance or transmittance of light in the ultraviolet or visible wavelengths absorbed, reflected or transmitted. Commonly...

unijunction transistor

A three-terminal semiconductor having only one PN junction and a stable, open-circuit, negative-resistance property.

unipolar

Refers to the transistors in which the working current flows through only one type of semiconductor material, either P-type or N-type. In unipolar transistors, the working current consists of either...

unmanned aerial vehicle

An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot onboard. UAVs are remotely controlled or autonomously operated, and they can be used for various...

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 etching

Also known as cathodic etching. Surface etching achieved by bombarding an evacuated surface with gas ions.

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.

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...

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.

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.

velocity modulation laser spectroscopy

A method of measuring negatively charged phase ions using a color-center or lead-salt diode laser.

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...

VGA

video graphics array

video graphics array

A display standard no longer in use and originally defined for IBM PCs, with 640 3 480 pixels in 16 colors and a 4:3 aspect ratio. There is also a text mode with 720 3 400 pixels. The standard has...

video measuring gauge

A device that calibrates the size, position or distance of objects imaged on a video screen.

video subtractor -> image comparison

A method used in imaging to detect subtle differences between two apparently similar pictures. It can be achieved by superimposing the negative of one photograph over a contact print of another, by...

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...

visual detection and ranging

Visual detection and ranging (ViDAR) is a technology that utilizes optical sensors, such as cameras or other imaging devices, to detect and track objects in the surrounding environment. Unlike...

Voigt effect

The induced birefringence in isotropic gases that results when the gases are placed in strong fields.

Wadsworth mounting

A system used for gratings that consists of a concave mirror, a grating and a plate holder mounted normal to the grating to reduce astigmatism and spherical aberration. The mounting yields a...

wafer

In the context of electronics and semiconductor manufacturing, a wafer refers to a thin, flat disk or substrate made of a semiconducting material, usually crystalline silicon. Wafers serve as the...

wave number

The frequency of a wave divided by its velocity of propagation; the reciprocal of the wavelength.

wave optics

Also referred to as physical optics - the area of optics in which the wave nature of light is essential when defining its propagation. To exploit the wave phenomena of light, one must interact light...

wave splitting

Any type of interference produced by a beamsplitter.

wavefront

A wavefront refers to the continuous surface or boundary representing points in a wave that are in phase, meaning they have the same phase or position in their respective cycles. In simpler terms,...

waveguide laser

Gas laser in which the tube acts as a channel for the laser beam.

waveguide nonreciprocal device

A device that consists of two types of mode converters, one of which must be magnetic. It is nonreciprocal because the coupling constants of the two mode converters have a different phase relation...

Photonics Dictionary