Photonics Dictionary: F

The length of the small space within which the atmosphere exhibits coherence, particularly in relation to an observer on Earth viewing celestial objects. The turbulence of the Earth's atmosphere...

A calculated function that can be achieved experimentally with interferometric analysis of complex atmospheric altitude; expressed as a relation to the turbulence integrated over the entire...

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

The product of Avogadro's constant and the electrical charge of an electron; thus, the electrical charge carried by 1 gmol of a substance, or approximately 9.65 x 104 C.

The signal-to-noise ratio (SNR) obtained with a Fourier transform spectrometer when detector noise prevails, which exceeds the SNR of a scanning spectrometer in the same time by a factor proportional...

The mathematical expression of the probability of any given state of energy being occupied when a semiconductor is in thermal equilibrium.

A crystal capable of being polarized in the reverse direction when an electric field is applied.

The lowest frequency at which the magnitude of the fiber transfer function decreases to a specified fraction of the zero frequency value. Often, the specified value is one-half the optical power at...

A property of optical fiber that results from thermal stresses during manufacturing and is defined as the amount of curvature over any specified length of fiber.

A fiber laser is a type of laser in which the active gain medium is an optical fiber doped with rare-earth ions such as erbium, ytterbium, or neodymium. Fiber lasers generate coherent light through...

A fiber optic preform is a cylindrical glass rod or tube used as the starting material for manufacturing optical fibers. It serves as the precursor from which optical fibers are drawn. The process 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...

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 procedure applied to flame-excited line emissions to determine spectra and wavelengths.

A frame taken with a CCD camera of a surface that is evenly illuminated by diffuse light. This frame shows irregularities in the light-sensing ability of the CCD, such as electronic defects and dust...

A flexible display refers to a type of electronic visual display that is designed to be bendable, foldable, or rollable, allowing for unconventional form factors and enhanced portability. Unlike...

The analysis and measurement of the fluorescence emitted by a source. Fluorometric processes are more sensitive than light absorption methods and are rapidly being applied in medical and biological...

1. The sector of the Earth's surface registered upon a remote sensing device in a satellite. 2. The amount of space occupied by a component on the surface upon which it is mounted. 3. The space on an...

A solid-state laser consisting of active atoms or ions of a transition metal, rare-earth metal or actinide, imbedded in a crystal or glass material, often garnet. Excitation and transfer to different...

The restricting aperture located at the front of the lens. It is usually defined as the maximum diameter of the entrance cone at the front vertex, for the specified field of view at infinity focus.

An optical reflector with the reflective coating applied to the front surface of the substrate. This eliminates the ghost image formed with second-surface mirrors.

1. The combination of the effects of two or more stimuli in any given sense to form a single sensation. With respect to vision, the perception of continuous illumination formed by the rapid...