Photonics Dictionary

A semiconductor diode operating in either a coherent or incoherent mode that is used as a near-infrared or visible source in triggering light-activated devices.

A semiconductor device with the property of conducting current more easily in one direction than the other. It has two terminals containing a single crystal of semiconducting material that ranges...

Visible laser radiation, often optically expanded and collimated, used to induced temporary blindness from within a walking distance of an impending target. Laser dazzle systems may be in a handheld...

Usually consists of a set of filters that attenuate specific wavelengths but transmit as much visible radiation as possible.

The pattern of physical or chemical changes that has taken place in a photographic emulsion, by its exposure to light, that will form a visible image when the emulsion is developed. Also known as...

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...

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

A crystal often used for windows and refracting components in the ultraviolet, visible and infrared. Characteristically, this form has excellent transmission from 0.14 to 6.0 µm.

A long-pass filter is an optical filter that allows longer wavelengths of light to pass through while blocking or attenuating shorter wavelengths. These filters are designed to transmit light with a...

A lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In other words, the lumen measures the total amount of visible light emitted by a...

Luminescence is the emission of light that occurs without the involved substance undergoing a significant increase in temperature. In other words, it is the production and emission of light by a...

Pertaining to electromagnetic radiation as perceived by the eye; that is, with the contributions as wavelengths in the visible region weighted according to V(λ), which symbolizes the spectral...

Descriptive of the radiant power of visible light modified by the eye response. It is the measure of the flow of visible light energy past any given point in space in a given time period, and is...

A spectrum that is continuous in the UV region with borders ranging from the visible to 300 A and lower.

In optical fiber, bends that are larger than microbends (see microbending), being visible. Generally they are caused by bending the cable beyond the specified bend radius. Light escaping at the bends...

In astronomy, the relative brightness of a celestial body. Originally a scale from 1 to 6, where 1 represented the brightest and 6 the faintest visible night sky objects. This scale has been expanded...

An acronym for microwave amplification by stimulated emission of radiation. Predecessor to the laser, the maser or 'microwave laser' was the first device to produce coherent electromagnetic waves,...

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...

A microchannel plate (MCP) is a specialized electron multiplier device used in various applications such as particle detection, imaging, spectroscopy, and night vision technology. It consists of a...

A microscopic crystal found in an intricately crystallized substance that is only visible under a microscope.

Characteristic of an object so small in size or so fine in structure that it cannot be seen by the unaided eye. A microscopic object may be rendered visible when examined under a microscope.

Microscopy is a scientific technique that involves the use of microscopes to observe and study objects that are too small to be seen with the naked eye. Microscopes are instruments that magnify and...

Multispectral imaging is a technique that involves capturing and analyzing images at multiple discrete spectral bands within the electromagnetic spectrum. Unlike hyperspectral imaging, which acquires...

E.I. duPont's trade name for a polyester film. The most practical beamsplitter for use beyond the 15-µm wavelength because of its high efficiency. It exhibits high visible transmission, allowing...

Nd:YAG laser refers to a solid-state laser that utilizes neodymium-doped yttrium aluminum garnet (Nd:Y3Al5O12) as the gain medium. This type of laser emits light at a wavelength of 1064 nm in the...

A near-infrared (NIR) camera is an imaging device designed to capture images in the near-infrared region of the electromagnetic spectrum. The near-infrared spectrum typically extends from about 700...

Near-infrared spectroscopy (NIRS) is a non-invasive analytical technique that uses the near-infrared region of the electromagnetic spectrum to study the absorption of light by molecules in a sample....

A light source, such as the sun or an incandescent lamp, that freely penetrates ordinary glass bulbs and emits in the near-ultraviolet (wavelengths ranging from about 300 to 400 nm). A mercury vapor...

A form of liquid crystal with an appearance of moving, threadlike structures, particularly visible when observed in thick specimens with polarized light. During this phase, the molecules of the...

A coating applied to a neutral density glass that is designed to reduce the amount of light evenly across the transmitted light spectrum with no color distortion. These coatings are designed to...

The nondestructive analysis and recording of industrial components based on the absorption of relatively low-energy neutrons by material having low atomic numbers. The visible image formed by the...

A device that uses low-level visible radiation or infrared radiation to produce a visual image of a night scene. These devices may rely on the amplification of existing visible light by...

A device consisting of a disc with a spiral arrangement of holes that is used to convert visible patterns into electrical patterns. Light is reflected from the subject and focused through a vertical...

A nitrogen vacancy (NV) refers to a specific type of defect or impurity in a crystal lattice where a nitrogen atom replaces a carbon atom adjacent to a vacancy (an empty lattice site) in the diamond...

A color whose hue is not produced by a single wavelength in the visible spectrum, but is instead produced by mixing the longest (red) and shortest (blue) wavelengths of the spectrum such as any...

A common technique in microscopy, oblique illumination is one in which the object is illuminated by a light source that is at an oblique angle (on the side) to the optical axis. This technique is...

The use of retroreflective projection technology (RPT) to project a background image onto a masked object, such as a vehicle or overcoat, thereby making the masked object appear invisible....

Optical cements and adhesives are specialized materials used in the assembly and bonding of optical components in optical systems. These materials are designed to provide secure and durable bonds...

The amount by which an optical surface deviates from its ideal design value, expressed in wavelengths of light. Optical manufacturers use this value to determine two common characteristics of an...

An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical filters are used to control the spectral content of light in various...

The fluorographic method whereby the visible image (as opposed to the x-ray image) is photographed by mounting a camera in front of the fluorescent screen.

A laser-pumped crystal with nonlinear optical properties inside of an optical resonator in which the output generates coherent light whose output can be tuned continuously over a variety of infrared...

An instrument for determining the temperature of a hot object by examining the color spectrum of the visible light it gives off and comparing it to the known temperature and wavelength spectrum of...

The process by which an atomic system changes from one energy level to another by either the emission or absorption of visible, infrared or ultraviolet radiation.