Photonics Dictionary: F

Observed lengthening in wavelengths of the optical absorption edge of a semiconductor with the application of an electric field.

The process whereby a rotating wheel carries grains of an abrasive, suspended in a vehicle, across the surface of the optical glass to be ground. The workpieces are forced downward by pneumatic...

A type of internal photonic connection in an integrated circuit in which a holographic grating is used to focus light at points on a silicon chip, maximizing the speed of signal propagation.

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...

A nonlinear optical process in which the frequency of an optical beam is doubled coherently.

A unit of frequency equivalent to 1012 cps. Named for Augustin Jean Fresnel, a French physicist known for his work in light and optics.

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...

Fresnel reflection refers to the reflection of light at the interface between two different media with different refractive indices. This phenomenon was named after the French engineer and physicist...

Reflection losses incurred at input and output of optical elements because of the difference in refractive index between glass and the immersion medium.

A method for measuring the index profile of an optical fiber by measuring the reflectance as a function of position on the end face.

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.

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.

The full width at half maximum (FWHM) is a measure used in various fields, particularly in spectroscopy, signal processing, and imaging, to characterize the width or extent of a distribution, peak,...

Optical fibers fused together to form a solid, vacuum-tight assembly in the form of a slab or rod. Discs or rectangular shapes having ground and polished surfaces perpendicular to the fiber lengths...

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...

Glass consisting of almost pure silicon dioxide (SiO2). Also called vitreous silica. Frequently used in optical fibers and windows.

A splice accomplished by the application of localized heat sufficient to fuse or melt the ends of two lengths of optical fiber, forming a continuous single fiber.