Photonics Dictionary

Nonimage-forming light, concentrated or diffuse, that is transmitted through the lens to the image. It is frequently the result of reflections from lens surfaces, a lens barrel, shutter or lens mount.

Fluence is a term used in various scientific and technical disciplines to describe the amount of something per unit area. The specific meaning of fluence can vary depending on the context in which it...

1. The sector of the Earth's surface registered upon a remote sensing device in a satellite. 2. The amount of space occupied by a component on the surface upon which it is mounted. 3. The space on an...

A phenomenon that occurs in WDM and DWDM systems when three closely spaced signal wavelengths near the zero-dispersion wavelength interact with each other, producing a fourth wavelength that...

Free-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the transmission of data using modulated beams of light through free space (air or a...

A Fresnel lens is a type of optical lens that consists of a series of concentric grooves or steps carved into a flat, thin piece of transparent material, typically plastic or glass. This design...

Fresnel reflection refers to the reflection of light at the interface between two different media with different refractive indices. This phenomenon was named after the French engineer and physicist...

Fusion ignition refers to the point in a controlled nuclear fusion reaction where the energy released by the fusion reactions becomes self-sustaining, leading to a continuous release of energy...

A galvanometric scanner, also known as a galvanometer scanner or galvo scanner, is a type of optical scanning device used to rapidly and precisely direct a laser beam or other light source to...

The global ecosystem dynamics investigation (GEDI) lidar is a state-of-the-art spaceborne instrument designed to study Earth's forests and ecosystems in three dimensions. Developed by NASA, GEDI is...

An optical mounting device that permits adjustment around two perpendicular and intersecting axes of rotation.

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or phosphoric oxides. Common window or bottle glass is a mixture of soda,...

A thermal radiation detector consisting of a small cell with a blackened plastic front face that bulges slightly when heat is received by it. The bulging tilts a small mirror, which, in turn, varies...

Transparencies that represent progressive steps in the amount of transmitted radiation for administering predetermined amounts of radiation to a radiation-sensitive substance. The steps are...

A gyroscope is a mechanical device consisting of a spinning disk or wheel mounted on a spinning axis in such a way that its orientation remains fixed regardless of any movement of its mounting...

A mount that uses a floating suspension and a motor-driven gyroscope to keep a motion picture or still camera at a set angle even though the camera is mounted in a place that subjects it to heavy...

A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a tungsten filament surrounded by a small amount of halogen gas, such as...

A lamp designed to emit a large amount of infrared radiation; used in applications requiring heat.

A device having a plane mirror so mounted that it can be set to reflect sunlight into a piece of laboratory equipment. It is driven by a clock to compensate for the sun's daily motion around the pole...

A compact optical projection system, mounted on or built into a helmet, and used to project data or a scene directly into the eyes of the wearer. Also called visually coupled display.

Also known as HCS, an analytical method designed to collect statistically relevant amounts of quantitative data on many parallel cell populations or processes within cells through the combination of...

A hydrogel is a three-dimensional network of polymer chains that are hydrophilic, meaning they have a strong affinity for water. This network structure allows hydrogels to absorb and retain large...

An electron tube that is used as a camera tube for a television system. When the picture to be transmitted is focused on a photosensitive surface, electrons are emitted from each section of the...

The digitization process by which an image is manipulated to increase the amount of information perceivable by the human eye.

A radiation detector with its active medium mounted within a lens that focuses the radiation signal. The improvement in detector performance is a function of the indices of refraction of the lens...

Qualitatively, the inverse of the amount of velocity produced by the application of a sinusoidal force to a system; therefore, if velocity is high, impedance at that point is low. Quantitatively,...

In the context of optical materials, the term "impurity level" refers to the presence of foreign atoms or molecules within the material that deviate from its regular or intrinsic composition. These...

Inductance is a fundamental property of an electrical circuit or component that describes its ability to store energy in a magnetic field when an electric current flows through it. It is typically...

Inertial confinement fusion (ICF) is a method of achieving nuclear fusion, a process where two atomic nuclei combine to release energy. In the case of inertial confinement fusion, the fusion reaction...

Inertial fusion energy (IFE) refers to a proposed method of generating electricity by harnessing the energy released from the fusion of light atomic nuclei, typically isotopes of hydrogen, through a...

A system that uses infrared detectors and related instrumentation to determine when abnormal amounts of infrared radiation, usually in the form of heat, are present in an area; used for the detection...

An infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating infrared (IR) radiation within the infrared spectrum. These lenses are used in...

A process by which a plastic cell is molded around a glass lens or lenses to create a mount, eliminating the metal barrel and the need for glass-to-metal seals.

An infrared detector mounted directly on the cold finger of the Dewar cooler rather than at the interface of Dewar and cooler, resulting in decreased size and power consumption and greater...

A lens that has a mount, usually bayonet or screw type in design, that can be used on a camera in place of lenses with the same mounting. This allows one camera body to be used with lenses of...

The creation of free electrons within a solid by the absorption of a sufficient amount of photons. The effect produces an increase in the conductivity of the solid.

A nonoptical surface, within lenses and lens mounts, that contributes largely to flare by reflecting light into the image space. As a result, such surfaces, so located, are finished with a dull...

The internet of things (IoT) refers to a network of interconnected physical devices, vehicles, appliances, and other objects embedded with sensors, actuators, software, and network connectivity....

The amount of energy required for a particular kind of atom to remove an electron to infinite distance. The ionization potential is usually expressed in volts.

A mechanical device designed to smoothly vary the effective diameter of a lens, thereby controlling the amount of light allowed through.

A small defocused Galilean telescope mounted in a hole in a door. Viewed from inside through the positive lens, a wide-angle view of the outside is seen; viewed from outside through the negative...

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 measurement of the hardness of a material as determined by the penetration depth of a diamond stylus under a specified amount of pressure.

The process by which laser emission is used in measuring fluid velocity and, more specifically, the detection of air and wind velocity.The laser technique measures the amount of frequency shift...

A laser diode module is a compact device that incorporates a laser diode, optics, and often other components into a single package. These modules are designed to provide a convenient and efficient...

Laser-induced breakdown spectroscopy (LIBS) is an analytical technique that uses a high-powered laser pulse to ablate a small amount of material from a sample, creating a plasma. This plasma emits...

A lateral shearing interferometer is an optical device used in interferometry to measure phase differences between two beams of light. Interferometry is a technique that combines and analyzes...

The metal tube that maintains the optical components of a lens in proper relationship. Some lenses are mounted in metal cells, which in turn are screwed to the front and rear of a shutter or lens...