Photonics Dictionary

Free of coma.

A type of geometrical distortion that brings about a trapezoidal display of a nominally rectangular picture. Usually produced when a picture is projected abnormally to the screen.

A mount for an optic element or optics assembly, designed so that all six degrees of freedom are singly constrained. This assures that movement will be prevented, while stress will not be introduced...

A cathode-ray tube that serves as a picture tube in a television receiver. The signal representing the picture intensity is transmitted to the electron gun grid so that the beam intensity varies with...

A lab-on-a-chip (LOC) is a miniaturized device that integrates various laboratory functions and capabilities onto a single, compact chip. Also known as microfluidic devices, lab-on-a-chip systems are...

A scanning laser radar system applied to transmission and concentration analysis in three dimensions of clouds as well as aerosols and other particles within atmospheric systems.

Laser parameters are the characteristics that define the behavior and performance of a laser. These parameters can be categorized into several groups: spatial, temporal, spectral, and operational. ...

Laser powder bed fusion (LPBF) is a type of additive manufacturing (AM) or 3D printing technology that uses a high-power laser to selectively fuse or melt layers of powdered material to build up a...

Laser scanning is a technology used to create precise digital representations of physical objects or environments by capturing their surface geometry and appearance. It involves directing a laser...

Laser sintering is an additive manufacturing (AM) or 3D printing technology that involves using a laser to selectively fuse powdered materials, typically polymers or metals, layer by layer, to create...

A machining process that uses a laser to cut three-dimensional molds or models.

Latency is the time interval between the stimulation or input of a system and the response or output. It is a measure of the time delay experienced in a system, network, or process. Latency can occur...

Lens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance, quality, and characteristics of lenses. These instruments are essential for...

An ophthalmic instrument used to measure the magnitude and direction of the maximum and minimum powers of a spectacle lens, and mark the optical center of the lens by an ink dot. When the lens to be...

An array or mosaic of optical surfaces. May be a number of lenses closely packed to form multiple images or many parallel cylinders used as a projection screen.

A type of additive color photography using a lenticular structure impressed on a film base and a camera lens with a filter having three sectors of red, blue and green. Exposure of the film through...

A type of stereoscopic photography in which a pair of lenses focuses a pair of images, relative to the positions of the two eyes, onto film through a lenticular screen, which records the images as an...

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 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...

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...

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

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

An LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs are widely used in various applications due to their energy efficiency,...

A device used to accelerate the electrons in a free-electron laser. There are several types, including the induction linear accelerator, the radio frequency linear accelerator and the superconducting...

Liquid crystals are a state of matter that exhibits properties intermediate between those of conventional liquids and solid crystals. In a liquid crystal, the molecules are ordered like those in a...

Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based semiconductor technology to create high-resolution, high-quality images. LCoS...

Liquid or fluid optics refers to the use of liquids to create or enhance optical systems. These systems leverage the unique properties of liquids, such as their ability to change shape, refractive...

Lithium triborate, commonly abbreviated as LBO, is a nonlinear optical crystal widely used in various applications involving frequency conversion of laser light. It is valued for its excellent...

Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main categories based on wavelength: near-infrared (NIR), mid-wave infrared...

A subtractive colorimeter that expresses a liquid's or object's color as a combination of three colors. These colors are developed through viewing the specimen object through three series of slides,...

A lymphocyte is a type of white blood cell (leukocyte) that plays a central role in the immune system. Lymphocytes are produced in the bone marrow and mature in the lymphoid organs, such as the...

A Mach-Zehnder interferometer is an optical device used to measure the phase difference between two collimated beams of light. It is named after the physicists Ludwig Mach and Ludwig Zehnder, who...

Machine learning (ML) is a subset of artificial intelligence (AI) that focuses on the development of algorithms and statistical models that enable computers to improve their performance on a specific...

A fluid having three components: a carrier fluid, magnetite particles suspended by Brownian motion and a stabilizer to prevent agglomeration of these fine particles. A magnetic fluid is characterized...

A thick meniscus lens arranged concentric with the center of curvature of a spherical mirror to produce an image free of spherical aberration.

1. A framelike structure that serves to restrict the viewing area of the screen when placed before a television picture tube. 2. In photolithography, a photomask (or mask) is typically a patterned...

With respect to television, that part of a color television circuit that combines the I, Q and Y signals, and changes them into single red, green and blue signals applied to the picture-tube grids.

A term used to describe a nondirectionally diffusing surface that, when illuminated, appears equally bright from all angles. An example of this kind of surface is the screen used for the forward...

A diagram used to represent the trichromatic variables of the components in a three-color combination.

A gauge designed to measure high degrees of vacuum. It consists of a glass bulb attached to the vacuum vessel, the measurement being made by filling the bulb with mercury and observing the volume of...

A lamp that has mercury in a tube or bulb that has first been evacuated. The electricity travels through the vapor between the electrodes and produces a blue-green light that is rich in ultraviolet...

A sensing or image-forming detector that serves to convert infrared rays into visible signals for communication purposes. Also, a form of telescope that generates visible images on a fluorescent...