Photonics Dictionary: F

The properties of certain materials that cause them to have relative permeabilities that exceed unity. This permeability permits the materials to exhibit hysteresis.

That radiation characterized by wavelengths ranging from 0.2 to 0.3 µm in the electromagnetic spectrum.

Describes incident radiation propagating parallel to an externally applied magnetic field in magneto-optical experimentation.

The effect discovered by Faraday in 1845 whereby nonoptically active materials or substances become capable of rotating the polarization plane of polarized radiation (light) passed through them when...

Ferroelectric materials are a type of dielectric materials that exhibit spontaneous electric polarization, meaning they possess a permanent electric dipole moment even in the absence of an external...

The phenomenon whereby certain crystals exhibit spontaneous electric polarization. It is analogous with ferromagnetism.

A fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and other components that are assembled together to facilitate the transmission of...

A fiber optic sensor is a device that uses optical fibers to detect and measure physical, chemical, biological, or environmental parameters. Unlike traditional electrical sensors, fiber optic sensors...

A flowmeter is a device used to measure the flow rate or quantity of a fluid passing through a particular point in a system. It works by sensing the velocity of the fluid passing through it and...

Fluorescence is a type of luminescence, which is the emission of light by a substance that has absorbed light or other electromagnetic radiation. Specifically, fluorescence involves the absorption of...

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....

An alteration in the direction of the magnetic induction at the interface between two media of different permeability.

A coil used to focus an electron beam by the generation of a magnetic field parallel to the beam.

Decrease in cosmic ray activity that is observed approximately 24 hours after a solar flare, attributed to a shielding effect produced by magnetic fields contained in the plasma of the cloud emitted...

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...

With reference to electromagnetic radiation, the number of crests of waves that pass a fixed point in a given unit of time, in light or other wave motion. Expressed in hertz or cycles per second.

Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin concentration in the brain. It utilizes near-infrared light to penetrate the...

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...