Photonics Dictionary: F

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

1. Also known as near-field diffraction. The field of radiation sent through an aperture in an absorbing screen at large distances as compared with the wavelength and the dimensions of the aperture,...

A single band in a group of light and dark bands that can be viewed in the periphery of Fresnel diffraction shadow.

A hologram formed with an object located close to the recording medium.

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...

Two plane mirrors that are not wholly located in the same plane. When light from a point source or slit reflects from the two mirrors, interference bands are revealed in the region where the light...

In a lens, the square of the radius of its aperture divided by the product of the focal length and the wavelength. It measures the importance of diffraction in the image formed by the lens. A small...

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 type of quarter-wave retarder in the form of a glass rhomb; light entering the retarder undergoes two total internal reflections, producing a change in phase.

A zone plate in which the zones are alternately transparent and opaque to specific radiation, and coarse enough so that no appreciable diffraction or focusing takes place. The Fresnel zone plate is...

1. A lens situated at or near the plane of an internal image to project the aperture of a previous objective or erector upon the aperture of a following lens. 2. A lens at or near the plane of a...

The series of images formed when periodic objects are exposed to collimated monochromatic radiation and that result from Fresnel diffraction.