Definitions: T

An arc discharge tube having a grid that is used to start the discharge through an atmosphere of inert gas or vapor at low pressure.

A family of semiconductor switching devices of which the silicon-controlled rectifier and the triac are most commonly used. They are fabricated from four positive and negative alternating layers.

Protective material surrounding the cladding of an optical fiber that allows the fiber no play within it.

The amount of time needed for a detector signal or electronic circuit to reach 63 percent of its final value after a fixed incident power is first applied.

A method of scanning in which a frame transfer device produces a continuous video image of a moving object by means of a stack of linear arrays aligned with and synchronized to the movement of the...

The process or device by which more than one signal can be sent over a single channel by using different time intervals for the different signals. This may be done by varying the pulse duration,...

The time domain is a concept used in signal processing and analysis to describe signals in terms of their behavior over time. In the time domain, signals are represented as functions of time, showing...

(TOF) The length of time needed for a signal to arrive at and be reflected from the target. The basis of an active autoranging/autofocus system.

The elongation of a transmitted data pulse through a fiber optic due to the chromatic dispersion of the fiber material.

Multiple exposures of holograms, one for each position of a vibrating image, that are used for vibration analysis and that yield a record of the time-averaged irradiance distribution at the hologram...

Although low in sensitivity (approximately 10-7 m for helium-neon lasers), this holographic technique permits quantitative assessment of entire vibratory patterns of given structures in a single...

Time-correlated single photon counting (TCSPC) is a technique used in photon counting applications, particularly in the field of experimental physics, biophysics, and fluorescence lifetime imaging...

See optical time-domain reflectometry (OTDR).

A cine camera that exposes a series of individual frames to record the changes in a subject that slowly alters with time. This results in the eventual showing of an event that happened over an...

Time-lapse optical coherence tomography (OCT) refers to a medical imaging technique that captures a series of sequential OCT scans over time, allowing for the dynamic observation and monitoring of...

A laser fitted with up to eight optical fibers that transmit the energy to different workstations in turn.

A time-to-amplitude converter (TAC) is an electronic circuit that converts a time interval between two events into an amplitude or voltage signal. TACs are commonly used in various scientific and...

Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial resolution provided by a sharp metallic or dielectric tip. TERS allows...

A spectroscopic technique that combines the high chemical specificity of Raman scattering and signal sensitivity provided by surface plasmon resonance enhancement, with the nanoscale spatial...

The study of the optical properties of living tissue. Increased understanding of the behavior of light in this varied, turbid medium, especially its scattering and absorption characteristics, is...

The use of a surgical laser instead of sutures or staples to close a wound or rejoin severed blood vessels.

A Ti:sapphire laser is a type of solid-state laser that utilizes a titanium-doped sapphire crystal as the gain medium. The name Ti:sapphire comes from the combination of titanium (Ti) as the dopant...

Housing that resembles a small metal can for a semiconductor component, photodetector or similar device.

In a local area network, a unique signal that travels from one node or station to another, providing them serially with access to the network for sending data.

In fiber optics, the annular region between two concentric circles; used to specify fiber cladding and core sizes.

The determination of the degree to which a manufactured component can deviate from its ideal specifications of material and geometry without impairing its performance.

Technique that defocuses activity from surrounding planes by means of the relative motions at the point of interest.

A variation of tomography in which several photographs of a patient are taken at different angles, and back-projection of the resulting radiographs produces light distribution in a chosen...

The distribution of gray-scale values in an image.

A symmetrical, very wide-angle lens. Well-corrected for spherical aberration and color, the Topogon can cover fields up to 90° at speeds from f/11 to f/6.3.

Topological photonics is a branch of physics and optics that explores the application of topological concepts to the behavior of light in photonic systems. Drawing inspiration from the field of...

Topology is a branch of mathematics that focuses on the properties of space that are preserved under continuous deformations, such as stretching, crumpling, and bending, but not tearing or gluing....

A lens having one or more toric surfaces. A toric surface is one having a maximum power in one meridian and a minimum power in a perpendicular meridian. In ophthalmic optics, toric lenses are used to...

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 intersect its center. The result is a surface having different curvatures in...

A calculated measure of the ability of an incident force to cause an object to spin. The spin speed of any given object is a direct function of the duration of the torque application.

A unit of pressure of 1 mm Hg, equivalent to 133 P. One atmosphere = 760 torr. (t).

The luminous flux emitted by a light source in all directions.

Image displacement by a decentered lens, rotated on a chuck whose axis of rotation passes through the geometrical center of the rim of the lens, when the light source is at an infinite distance. It...

The lateral distance between a vertical line drawn through the geometrical center of the distance portion of a multifocal, and a vertical line penetrating the geometrical center of the segment.

Total internal reflection fluorescence (TIRF) microscopy is an advanced fluorescence microscopy technique that leverages the principle of total internal reflection to selectively illuminate and image...

The reflection that occurs within a substance because the angle of incidence of light striking the boundary surface is in excess of the critical angle.

Also known as a pyrradiometer. An instrument that is designed to measure heat radiation nonselectively; e.g., the combination of terrestrial and solar radiation.

A naturally occurring crystalline mineral that has the property of polarizing transmitted light. It is little used now that the Polaroid sheet is available.

Effect whereby two electrons lose synchronism with the accelerating field and are lost during synchronous radiation. The effect is produced by the scattering of the electrons that are oscillating in...

In a cathode-ray tube, the visible line or lines formed on the screen by the deflection of the electron stream.

1. The process of following an object's movement; accomplished by focusing a radar beam on the reticle of an optical system on the object and plotting its bearing and distance at specific intervals....

Measurement of a translation stage's deviation from absolute straightness, that is, its angular motion in both the vertical and the horizontal planes.