Photonics Dictionary

A means of determining a prism's index of refraction by placing the prism so that its emergent face is perpendicular to the incident beam. This arrangement permits the determination of the prism's...

Entirely analogous to color photography, but inclusive of light bands that do not appear in the visible spectrum.

An image-forming instrument in which a strong electrostatic field causes cold emission of electrons from a sharply rounded point or from an object that is located on that point. The electrons are...

An extremely powerful microscope that renders individual ionized atoms visible by using an electric field to propel the ions to a fluorescent screen where they are magnified.

The field of view (FOV) refers to the extent of the observable world or the visible area that can be seen at any given moment through a device, such as an optical instrument, camera, or sensor. It is...

Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and non-human primates. The name "filovirus" is derived from their filamentous...

A filter, partially opaque to near-ultraviolet, visible and infrared radiation, that may be made by exposing and processing photographic film. Such materials are almost equally opaque to radiation of...

The photographic recording of a subject that exhibits luminescence only for an extremely short time (10-8 s) after the exciting source is removed. In the process, the subject may be illuminated by...

A tube containing mercury vapor and lined with a phosphor. When current is passed through the vapor the strong ultraviolet emission excites the phosphor, which emits visible light. The ultraviolet...

A fluorescent screen refers to a phosphorescent or fluorescent-coated surface that emits visible light when exposed to other forms of electromagnetic radiation, such as x-rays or ultraviolet light....

The photographic recording of a visible image formed by the impact of invisible radiation on a fluorescent screen.

A fluorophore is a molecule or a portion of a molecule that has the ability to emit light upon excitation by an external energy source, such as ultraviolet or visible light. The process by which a...

A laser skin-resurfacing method that creates microscopic thermal wounds referred to as microscopic treatment zones (MTZs), which are surrounded by uninjured tissue. The MTZs are usually arranged in a...

A free-electron laser (FEL) is a type of laser that generates coherent, high-intensity electromagnetic radiation by using a beam of accelerated electrons as the lasing medium. Unlike traditional...

A frequency comb is a precise and regular series of equally spaced spectral lines, or frequencies, that are generated with great accuracy. The term "frequency comb" is often associated with the Nobel...

Fused quartz and silica are closely related materials, both composed primarily of silicon dioxide (SiO2), but they are produced through different manufacturing processes and have distinct properties...

Gallium arsenide phosphide (GaAsP) is a semiconductor alloy composed of gallium (Ga), arsenic (As), and phosphorus (P). It is commonly used in the fabrication of optoelectronic devices, particularly...

A camera used in scintillation recording to make a visible record of the distribution and relative concentration of radioactive tracer elements in a sample that is undergoing scanning.

Gallium nitride-based light-emitting diodes (GaN-based LEDs) are semiconductor devices that emit light when an electric current passes through them. These LEDs are constructed using gallium nitride...

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,...

The Golgi staining technique (also called the black reaction) makes it possible to look at the nervous system by rendering neurons visible under light microscopy. After a long process involving...

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 glass filter that transmits visible light while absorbing infrared energy (heat).

A helium-neon (HeNe) laser is a type of gas laser that emits visible red light at a wavelength of 632.8 nm. It operates based on the principle of stimulated emission of photons from excited helium...

Radiation consisting of more than a single wavelength in the visible region of the spectrum.

High dynamic range (HDR) refers to a technology that allows for a broader and more dynamic range of luminosity in visual content, such as images or videos. It is particularly associated with displays...

A fish-eye lens designed to photograph cloud formations over the entire visible sky.

An infrared device used in satellites and rockets to determine a heat horizon for the Earth at altitudes (above 200 miles) where the visible horizon cannot be discerned. The device scans the infrared...

A mirror with a coating that reflects infrared radiation and transmits visible light.

Hyperspectral imaging is an advanced imaging technique that captures and processes information from across the electromagnetic spectrum. Unlike traditional imaging systems that record only a few...

An electron tube that employs electromagnetic radiation to produce a visual replica of an image produced on its cathode. Electrons ejected from the cathode by the incident radiation are accelerated...

An image intensifier, also known as an image intensification tube or image intensification device, is a specialized electronic device used to amplify low-light-level images to make them visible to...

A plane in which an image is formed. A real image formed by a positive lens would be visible upon a screen located in this plane.

The emission of light by thermal radiation of a temperature high enough to render the source of radiation visible.

The light formed by visible radiation that, in traveling from light source to object, undergoes one or more reflections. In microscopy, it is the light that falls on the object at right angles to the...

An InGaAs (indium gallium arsenide) camera is a type of imaging device that utilizes InGaAs sensors to capture images in the near-infrared (NIR) spectrum. InGaAs is a semiconductor material that is...

An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the infrared radiation emitted by objects, revealing temperature variations across...

An infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible spectrum of light. These detectors are utilized in various applications,...

An image converter that produces a visible image based on the infrared emittance of the object. The infrared energy is focused on a photocathode that emits electrons. These are accelerated and...

An infrared light source is a device that emits light in the infrared spectrum, which lies beyond the visible spectrum of light. Infrared light has longer wavelengths than visible light and is...

An infrared light-emitting diode (IR LED) is a semiconductor device that emits infrared light when an electric current passes through it. Similar to standard LEDs that emit visible light, IR LEDs are...

A type of microscope that uses radiation in the infrared region to illuminate objects that are opaque to visible radiation. The microscope consists of two illumination systems (transmitted and...

Infrared optics refer to optical components and systems designed to manipulate and control infrared (IR) light, which lies beyond the visible spectrum. These components are crucial for various...

A phosphor, such as sulfide or selenide, that can be excited to luminescence by incident infrared radiation simultaneous to or following its excitation by visible radiant energy.

Photographic recording that uses infrared radiation as the light source to form an image of a microscopic object and a system of lenses and objectives that are transparent to the radiation. The image...

An infrared source combined with reflecting projection optics to illuminate a target making it visible when observed through an infrared viewing device.

Infrared (IR) refers to the region of the electromagnetic spectrum with wavelengths longer than those of visible light, but shorter than those of microwaves. The infrared spectrum spans wavelengths...