Photonics Dictionary: L

Lidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and generate precise, three-dimensional information about the shape and...

The visual perception of contrasting forms is more difficult if the forms have the same luminance but different chromaticities, than if the forms have the same chromaticity but different luminances.

Electromagnetic radiation detectable by the eye, ranging in wavelength from about 400 to 750 nm. In photonic applications light can be considered to cover the nonvisible portion of the spectrum which...

The ability of the human eye to adjust itself to an alteration in the intensity of light.

A device that serves to emit light of the same wavelength as the input light, only with an increase in intensity. It may be a solid-state device comprising photoconductive and luminescent layers...

Light diffusion refers to the process by which light is scattered or spread out in various directions as it interacts with a medium or material. Unlike direct transmission through a transparent...

The process whereby white light is separated into its component wavelengths. Light beams of different wavelengths are separated from each other by undergoing a different angular deviation. Prisms and...

LiFi, short for light fidelity, is a wireless communication technology that utilizes visible light or infrared light to transmit data. Developed as an alternative or complementary technology to...

The term light field refers to the spatial distribution of light rays traveling in all directions through a given space. It includes information about the intensity and direction of light rays at...

Phenomenon caused by an ultrashort and ultra-intense light pulse propagating in a Kerr medium, such as air or water. When the pulse's power exceeds the critical power (approximately 3 GW in air),...

A homogeneous optical medium or coating that transmits only in particular regions of the spectrum. It is used to change or modify the total or relative energy distribution of a beam of light.

The term for an image captured by a detector and from which a dark frame, bias frame and/or flat-field frame can be subtracted during image processing.

Any device that is used to sense and measure light. See exposure meter; photoelectric exposure meter; photoelectric photometer; reflected light meter.

A device that is designed to modulate a beam of light, usually from a laser source, by acting upon the beam directly. The three general types of devices operate in an acousto-optic, electro-optic or...

That property of a substance that determines that there will be a decrease in conductivity when exposed to light radiation.

In optics, a pattern, such as the Buchmann-Meyer pattern, that may be viewed when the record surface is illuminated by a light beam having parallel rays.

A handheld, light-sensitive device that is used with a display console to directly change, measure or erase the visual information presented. Interfaced with the computer that is generating the...

A narrow cone of light rays that diverge from a point source or converge to an image point.

Transparent matter that usually is drawn into a cylindrical, pyramidical or conical shape through which light is channeled from one end to the other by total internal reflections. Optical fibers are...

The individual coherent series of lightwaves that defines a quantum of radiant energy. Light quantum is equal to hv, h being Plank constant and v being the radiation frequency in herts.

The path of a given point on a wavefront. One of the radii of a wave of light that indicates the direction of light travel.

Technique for measuring the volume bulk of materials as they move along a conveyor with an accuracy of better than 1 percent. Based on the use of high-resolution arrays of solid-state detectors, the...

Also known as single plane illumination microscopy (SPIM), this process was designed for imaging of sensitive samples and fast biological processes in vivo. In this method, a light sheet illuminates...

The generic term applied to all sources of visible radiation from burning matter to ionized vapors and lasers, regardless of the degree of excitation.

The electrical power used to stimulate any light source. Power supplies may be step-up or step-down transformers; rectifiers to convert AC to DC; ammeters and voltmeters to observe the input to the...

The fraction of incident light power in an optical modulator that is available to the output beam.

With respect to display systems, a device that uses an independent light source and a control-layer medium, the active optical element, to convert an electrical charge image to an optical image....

A PN-PN device with incident light taking the place of gate current; three of the four semiconductor regions are available for circuit connections.