Photonics Dictionary: I

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...

Luminous flux incident per unit area of a surface; luminous incidence. (The use of the term "illumination" for this quantity conflicts with its more general meaning.)

Characteristic of a surface or object that has luminous flux incident upon it.

A desklike apparatus with an opal glass surface illuminated from beneath by fluorescent tubes. It is equipped with roll holders for aerial films and a low-power microscope or some form of...

Generally, the orientation of rays of light striking a surface.

A photometric instrument used to measure the illumination falling on a surface. It may be photoelectric or visual.

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 distance from the last surface of a lens system to the image. For a thin lens system, this distance is equivalent to the distance from the rear nodal point of a lens to the image.

A semiconductor platelet laser that emits a coherent image by means of plane optical pumping over the platelet surface, and that uses laser threshold characteristics to produce a pronounced threshold...

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...

Flux incident per unit area of a surface.

A ray of light that falls upon or strikes a surface of an object such as a lens. It is said to be incident to the surface.

Indirect time-of-flight (iTOF) is a method used in 3D imaging and depth sensing to measure the distance to an object based on the time delay between the emission of a light pulse and the detection of...

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,...

A direct method of measuring refractive index that works best with flat-surfaced samples (i.e., those that are not dependent on special prism shapes) and produces data that are uniquely sensitive to...

Any object that emits radiation of a wavelength lying between about 0.75 to 1000 µm. A calibrated secondary source usually is a heated cavity (blackbody) or a filament lamp rated in wattage...

A vidicon that has a photoconductive surface that can be excited by infrared radiation.

An intensified charge-coupled device (ICCD) camera is an advanced imaging device that combines the capabilities of both an image intensifier and a charge-coupled device (CCD) sensor to achieve...

An interferometer is a scientific instrument that utilizes the principle of interference to measure differences in the path length, wavelength, phase, or amplitude of coherent electromagnetic waves....

Interferometric modulator display (IMOD) is a type of display technology used in electronic devices, known for its energy efficiency and ability to produce high-quality reflective color displays....

With reference to absorbance, absorptance, transmittance and the like, the processes occurring within a specimen between the entry and exit surfaces.

The ratio of the radiant power transmitted to the second surface of a medium to the corresponding radiant power that has just passed through the first surface. Internal transmittance does not denote...

An invisibility cloak is technology that would render an object or individual invisible to the observer. In scientific research, efforts to create real-life invisibility cloaks have been...

The ejecting of ions from the surface of a material.

Ion-beam sputtering (IBS) is a physical vapor deposition (PVD) technique used for depositing thin films onto substrates. It involves bombarding a target material with a beam of energetic ions,...

The gas of charged particles that begins approximately 50 km above the surface of the Earth and contains a sufficient quantity of electrons and ions to affect the propagation of radio waves.

The rainbow exhibition of colors, usually caused by interference of light of different wavelengths reflected from superficial layers in the surface of a material.

Radiant flux incident per unit area of a surface. Also called radiant flux density.

A curve or surface having equivalent light intensity.