Photonics Dictionary: H

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 three-dimensional interference pattern of fringes that is recorded on a holographic plate to facilitate the study of a complex object.

The interferometric analysis of a complex object by utilizing the three-dimensional hologram. By causing a laser beam to diverge into two directions, one of which directly strikes a holographic...

A photographic recording of interference patterns between a plane wave and a spherical wave on a high-resolution photographic emulsion.

A specific type of hologram that will transmit a pure plane wave when the hologram is illuminated by the type of wave it is matched to.

The storage of data as bits in memory by holographic processes. The laser beam is divided into reference and object beams, and bit information is stored as a hologram.

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...

The application of coherent wavefront techniques to the determination of the physical state of a system without appreciably altering that state.

A component used to modify light rays by diffraction; the HOE is produced by recording the interference pattern of two laser beams and can be used in place of lenses or prisms where diffraction...

A method of measuring flow velocity by seeding the flow with neutrally buoyant particles and using a pulsed laser to holographically record particle displacement during a short time period. An...

Holographic tomography is an advanced imaging technique that combines holography and tomography to provide three-dimensional reconstructions of transparent or weakly scattering objects with high...

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...

A series of permanent holograms in dichromated gelatin formed by opening total page-composer apertures and setting a point source of light in each storage location. It performs much like a...

With respect to a crystal, the characteristic of possessing two ends symmetrical with each other.

The perpendicular orientation of the molecular axes of the nematic molecules in a nematic crystal, relative to the electrode plates.

A system of sensors and related instrumentation that allows a navigable object (usually a missile) to locate its destination by some distinguishing characteristics of that target, and then calculate...

A term applied to rays that possess the same focal point, which may be infinity, thereby meaning that the rays are parallel.

A type of receiver utilizing a local oscillator phase-locked to the incoming signal.

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

The broadening of a laser's line width in a way that affects every atom (or molecule), and thus the whole system, in the same manner. Examples are collision broadening, and natural or intrinsic...

That part of the cladding wherein the refractive index is constant within a specified tolerance, as a function of radius.

A thin film of absorbing or nonabsorbing layers in which the absorption of radiation at any point is directly proportional to the electrical field intensity at that point.

The parallel orientation of the molecular axes of the nematic molecules in a nematic crystal, relative to the electrode plates.

X-rays of one frequency or a narrow band of frequencies.

A junction between semiconductors that differ in their doping level conductivities but not in their atomic or alloy compositions.

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...

An infrared device used in satellites and rockets to determine a heat horizon for the Earth at altitudes (above 200 miles) where the visible horizon cannot be discerned. The device scans the infrared...

In television, the period during which the electron beam is cut off while the raster returns from the right-hand side of the screen to the left.

A type of paper chromatography that produces a chromatogram that is horizontal instead of vertical.

A device that controls the output of a television receiver's horizontal oscillator.

In television, the number of individual pixels that can be distinguished in a horizontal scanning line; also called horizontal definition.

Horizontal concentrations that comprise the dominant factor in atmospheric gradient correction. The range bias near due north and due south azimuths coincides with the systematic decrease in surface...

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

The locus of the points in the field of binocular vision that are observed singly. The images of these points correspond to the respective retinal points.

A method of manufacturing polycrystalline infrared-transmitting optical fiber by heating a single halide crystal billet and forcing it through a die.

A mirror with a coating that reflects infrared radiation and transmits visible light.

Term applied to laser technology to denote an area of above-average intensity often attributable to atmospheric inconsistencies.

The center of a local area network in the star topology.