Photonics Dictionary: F

An optical resonator in which feedback is accomplished by two parallel planes. In diode lasers, the planes are obtained by cleaving, polishing, etching, etc.

A device in which slab geometry internally compensates for thermal-optic distortion; the solid host material -- glass or Nd:YAG -- is in the form of a rectangular slab with plane parallel faces. The...

The diffraction pattern of a source such as a light-emitting diode, injection laser diode or the output end of an optical waveguide observed at an infinite distance from the source.

A laser with output over a wide range of wavelengths spanning the far-infrared region of the spectrum (30 to 1000 µm); typically, it consists of a metal or dielectric waveguide one to two...

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...

A femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds, where one femtosecond is equal to 10-15 seconds. These lasers are capable of...

A fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It consists of a periodic modulation of the refractive index along the length...

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 spectrometer is a device used for measuring the spectral content of light. It utilizes optical fibers to transmit light from a source to a spectrometer unit, where the light is...

A fiber optic transceiver, often simply referred to as an "optical transceiver," is a device used in fiber optic communications to transmit and receive data over optical fibers. It integrates both a...

An expression of the tolerance of decentration of a laser diode from the optical axis: the region around the axis in the focal plane of the collimator in which the facet can be located and still...

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...

Fluence is a term used in various scientific and technical disciplines to describe the amount of something per unit area. The specific meaning of fluence can vary depending on the context in which it...

A device, also called a fluorescence lifetime instrument, that measures decay curves of fluorescing samples. It generally consists of a gated pulsed flashlamp or a cavity dumped dye laser...

A fiber optic device that uses a HeNe laser, beamsplitter, monochromator and photomultiplier to detect trace levels of chemicals and viruses in samples inside or outside the body.

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...

Freeform mirrors refer to reflective optical components that deviate from traditional symmetric or rotationally symmetric shapes, such as spheres or paraboloids. Unlike conventional mirrors, which...

A frequency comb is a precise and regular series of equally spaced spectral lines, or frequencies, that are generated with great accuracy. The term "frequency comb" is often associated with the Nobel...

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...