Photonics Dictionary

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...

Any system of time measurement that is based on atomic resonances. The transition times between the hyperfine levels of cesium-133 have been accepted as the international standard.

The action of a biological system responding to a single or multiple coherent particles of light produced from a laser source. Examples of laser biostimulation include: retinal interaction of light...

A photocathode that exhibits maximum sensitivity in the blue and ultraviolet regions of the spectrum. The sensitivity is obtained by the exposure of a thin layer of antimony to cesium vapor at an...

The interval between direction of signal to a light-emitting diode and attainment of 10 percent output current in the photodetector.

For a detector, the amount of time alotted for the observation of one location.

Uniform measure of time based on dynamics law and calculated according to planetary orbital paths; specifically, Earth's orbit about the sun.

The length of time during which the receiver is irradiated.

Measurement of the interval during which a photodetector's signal and output current drops from 90 to 10 percent.

Fluorescence lifetime refers to the average time it takes for a fluorophore, a molecule that absorbs light at one wavelength and emits it at another, to return to its ground state after being excited...

Fluorescence lifetime imaging (FLIM) is an advanced imaging technique that provides information about the lifetime of fluorescence emissions from fluorophores within a sample. Unlike traditional...

Time elapsed during the radiant output change from 10 to 90 percent of maximum in a light-emitting diode or laser. Usually expressed in nanoseconds and measured from the moment of onset of the...

A binary semiconductor compound used as a substrate or active layer for diode lasers.

A controlled random search process, such as generalized simulated annealing, that has been incorporated into many optical design programs as a way of helping designers find the most suitable lens...

A semiconductor material that is used as an infrared detector for light up to 5 µm in wavelength.

Integration time, in the context of optics, imaging systems, and sensor technology, refers to the duration over which a sensor collects and accumulates incoming light or signal. It is a crucial...

One of two types of solar time - the other being apparent solar time - the mean solar time is the time measured by the average hour angle position of the sun in the sky compiled over a period of one...

Computerized lens design algorithm that permits the lens MTF characteristic to be included and controlled during the optimization process. MTF optimizations typically allow lens design users to...

A technique that combines two or more imaging processes in order to minimize the disadvantages within each of the contributing processes. In medical applications, combining multiple modalities...

In an optical waveguide,- typically a multimode fiber - the distortion resulting from differential mode delay, i.e. axial rays (modes), with the shortest path length, will have the shortest...

A laser that produces emission in two or more transverse or longitudinal modes.

An optical waveguide that will allow more than one bound mode to propagate.

An instrument that measures several optical parameters, such as optical power and wavelength, with a single measurement input.

An optical time-domain reflectometer (OTDR) is a specialized instrument used in optical fiber communications to characterize and analyze the optical fibers' characteristics, including attenuation,...

A method for characterizing a fiber wherein an optical pulse is transmitted through the fiber, and the resulting light scattered and reflected to the input is measured (by an optical time-domain...

The ability of a vision system to interpret an image in a short enough time to keep pace with most operations.

The output of spectral channels written as an integral function of known solar irradiance, atmospheric transmittance and camera spectral responsivity, and the unknown spectral reflectance.

Measurement of the time elapsed during the current output change from 10 to 90 percent in a photoconductor.