Photonics Dictionary: H

A defect in the cleaved end face of an optical fiber, defined as multiple surface irregularities across the fiber surface. A less serious imperfection of the same nature is known as mist.

Harmonic generation refers to a nonlinear optical process in which incoming photons interact with a material and produce new photons at integer multiples of the frequency of the incoming photons....

An optical system that superimposes a synthetic display providing navigational or weapon-aiming information on a pilot's or driver's field of view. The system includes a cathode-ray tube, collimating...

A rangefinder used to determine the height or altitude of aerial targets by means of optical triangulation. The device employs the stereoscopic principle.

A helium-neon (HeNe) laser is a type of gas laser that emits visible red light at a wavelength of 632.8 nm. It operates based on the principle of stimulated emission of photons from excited helium...

A compact optical projection system, mounted on or built into a helmet, and used to project data or a scene directly into the eyes of the wearer. Also called visually coupled display.

In optical communications, the translation of optical signals into radio signals, lowering their frequency in detection from greater than 1014 Hz to less than 1010 Hz, so that further signal...

Property of a substance whose volume elements differ in composition and optical properties.

High harmonic generation (HHG) refers to a nonlinear optical process in which intense laser light interacts with a gaseous medium, typically an atom or a molecule, to produce harmonics of the...

Optical fiber in which the attenuation exceeds the normally acceptable level for long-haul or data communications use.

An infrared-transmitting optical fiber with a hollow core; it can be square, round or rectangular in cross section. Capable of carrying high laser power but subject to high bending losses.

A holographic camera, also known as a holographic imaging system or holographic recorder, is a specialized device used to capture 3D holographic images of objects or scenes. Unlike conventional...

A holographic grating is a type of diffraction grating that is produced using holographic recording techniques. It consists of a periodic structure of alternating transparent and opaque regions,...

The holographic recording of a microscopic specimen whereby magnification is achieved by alteration in a wavelength or radius of curvature between recording and reconstruction of the wavefront. With...

Holography is a technique used to capture and reconstruct three-dimensional images using the principles of interference and diffraction of light. Unlike conventional photography, which records only...

That property of a substance that determines that all components of volume are the same in composition and optical properties.

An optical test table made up of two outer layers or "skins'' bonded to either side of a honeycomblike core, usually of aluminum or steel. It results in equal quality with greatly reduced weight...

The rotation of an instrument (or the line of sight of an optical system) in a horizontal plane; transverse.

Device in which the various circuit elements are fabricated in different substrate materials and then appropriately joined together so that the various substrate materials can be chosen to optimize...

An optical fiber's absorption of electromagnetic waves due to hydroxyl ions remaining after contact with water.