Photonics Dictionary: I

The total optical power loss caused by the insertion of an optical component such as a connector, splice or coupler into a fiber optic system. See attenuation.

A small round mirror on the end of a handle used for viewing inside an inaccessible cavity.

Instantaneous field of view (iFOV) is a term commonly used in the context of remote sensing, imaging systems, and optical instruments. It refers to the specific portion of a scene that an optical...

The tendency to adjust an instrument such as a microscope so that the viewed image appears much closer than infinity.

A reflection hologram using multiple color lasers that integrates various graphical techniques to allow the display of three-dimensional images of live objects in motion, as well as outdoor scenes,...

A thin-film device containing miniature optical components connected via optical waveguides on a transparent dielectric substrate, whose lenses, detectors, filters, couplers and so forth perform...

Integrated photonics is a field of study and technology that involves the integration of optical components, such as lasers, modulators, detectors, and waveguides, on a single chip or substrate. The...

A set of international standards by which a single telecommunications channel is used to transmit voice and data simultaneously.

A hollow sphere coated internally with a white diffusing material and provided with openings for incident beam, specimen and detector used for measuring the diffuse reflectance or transmittance of...

Integration time, in the context of optics, imaging systems, and sensor technology, refers to the duration over which a sensor collects and accumulates incoming light or signal. It is a crucial...

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...

A CCD image sensor that uses a proximity-focused image intensifier to provide greater sensitivity at low light levels.

An interband cascade laser (ICL) is a type of semiconductor laser that operates based on interband transitions between energy bands in a semiconductor material. Unlike traditional semiconductor...

A filter that controls the spectral composition of transmitted energy partially by the effects of interference. Frequently, these filters are made up of thin layers of metals and dielectrics,...

A device, consisting of a diode activated by an interference pulse, that is designed to minimize the white spots on a television screen that are intensified by interference.

A special form of microscope that utilizes interference for observing and measuring the phase and optical thickness in completely transparent objects and specimen. The object is placed in one beam...

The spectrum produced by the interference of light provided that the source used to create the interference has a broad enough emittance to form a spectrum.

An instrument that employs the interference of lightwaves to measure the accuracy of optical surfaces; it can measure a length in terms of the length of a wave of light by using interference...

Heat measurement method in which the sample is made part of the interferometer and the temperature increase is determined by measuring the change in optical pathlength through the material. By moving...

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....

Interlayer attraction refers to the attractive forces between adjacent layers of atoms or molecules in a material, particularly in layered structures such as van der Waals solids, graphene, and...

In a heterodyne optical receiver, the frequency that is the difference between that of an incoming laser signal and that of the local oscillator laser. Also called beat frequency.

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...

A unit of measurement of luminous intensity based on a physical standard, a set of calibrated carbon filament lamps. The old candle unit was superseded by the new candle or candela.

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....

Measures the refractive indices axially from the fiber profile. Microscopy technique provides an interferogram with high contrast with demonstrated improvements in relation to the Pluta two-beam...

Sharp and narrow absorption lines found in the spectra of stars. They result from the absorption of a part of a star's emittance by interstellar gases.

Intravital microscopy is an imaging technique used to visualize biological processes within living organisms, typically in real-time. Unlike traditional microscopy, which involves the examination of...

A photodetector composed of a photoconductive material that, when exposed to radiation, conducts without the aid of added impurities and does not have to be cooled to the level of extrinsic material....

Loss intrinsic to the fiber caused by parameter (core dimension, profile parameter) mismatches when two nonidentical fibers are joined.

The absorption of a photon raising an electron across the forbidden gap from valence to conduction band of the semiconductor where conductivity is increased and incident radiation may be measured.

Collisional absorption of energy that occurs in inertial confinement fusion systems when hydrodynamic expansion of the plasma causes an electron passing through the field of an ion to absorb...

The law stating that the illuminance (or irradiance) from a point source varies as the inverse square of the distance between the source and the receiver.

An image that is similar to the object but rotated 180° about the axis of the system.

A microscope designed so that the specimen is located face down above the objective.

A filter that transmits infrared and ultraviolet but is opaque to visible radiation.

A development aimed at extending the life of a tungsten filament. The iodine vapor in the lamp envelope combines with the tungsten vapor emitted by the hot filament, but the compound is decomposed by...

A laser in which the transition involved in stimulated emission of radiation takes place between two levels of an ionized gas. The gases are electrically excited in a container called a plasma tube,...

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,...

A closed vessel with electrodes of different potentials that is used to determine how much ionization took place in a gas after its exposure to x-rays or radioactive emissions.

An electroradiographic process that uses ionization of air by x-rays as a basis for forming electrostatic images.

The adjustable membrane located just in front of the crystalline lens within the eye. The iris gives the eye its color. See also iris diaphragm.