Photonics Dictionary: F

A method of focusing an optical system by moving the front component (the lens closest to the subject) to change the distances between components. Also known as front-element focusing.

With respect to a unit cell in a crystal structure, the property defining an atom located at the center of each face.

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 spectroscopic technique used in the detection of free radicals by virtue of their electronic spectra. In this method, an intense light flash is used to form extensive photolysis and yield a high...

An electronic display in which a flat screen is formed by an orthogonal array of display devices, such as electroluminescent devices, light-emitting diodes or liquid crystal cells.

Flow cytometry is a powerful technique used in biology and medicine for the quantitative analysis of the physical and chemical characteristics of cells and particles suspended in a fluid. The method...

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 powerful method, referred to as FCS, for determining the average diffusion coefficients of fluorescent molecules in solution or membranes. FCS measurements rely on recording the transition of...

Fluorescence lifetime imaging (FLIM) is an advanced imaging technique that provides information about the lifetime of fluorescence emissions from fluorophores within a sample. Unlike traditional...

Fluorescence microscopy is a specialized optical imaging technique used in biology, chemistry, and materials science to visualize and study specimens that exhibit fluorescence. Fluorescence is the...

Fluorescent proteins are proteins that exhibit the property of fluorescence, which is the ability to absorb light at a specific wavelength and emit light at a longer wavelength. These proteins are...

A fluorophore is a molecule or a portion of a molecule that has the ability to emit light upon excitation by an external energy source, such as ultraviolet or visible light. The process by which a...

A microscope that uses a flying spot scanner, directed through the eyepiece, as a light source to determine the features of a transparent specimen. The flying spot is modulated by the varying density...

Förster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced fluorescent molecules. This phenomenon is named after the German scientist...

Free-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the transmission of data using modulated beams of light through free space (air or a...

A Fresnel lens is a type of optical lens that consists of a series of concentric grooves or steps carved into a flat, thin piece of transparent material, typically plastic or glass. This design...

FTIR (Fourier transform infrared) spectrometer is a powerful analytical instrument used to obtain an infrared spectrum of absorption or emission of a solid, liquid, or gas sample. It operates based...

Fused quartz and silica are closely related materials, both composed primarily of silicon dioxide (SiO2), but they are produced through different manufacturing processes and have distinct properties...