Photonics Dictionary

A specific gas-filled tube designed to illustrate the luminous effects of discharges through rarefied gases.

A rapid roughing process for the quick removal of glass, the first step in manufacture of a curved lens surface. It is accomplished with coarse emery or a diamond-impregnated tool.

The curved mark formed when, in the process of generating, a loose or coarse diamond particle from the generating tool scores the work so deeply that subsequent fine grinding or polishing cannot...

A device used to lock the internal synchronization generator of a television camera to an external source.

The position and shape of the image of a point source, as predicted by geometric optics alone. The geometric image is to be differentiated from the diffraction image, which is determined from...

A field of physics that deals with light as if it truly were composed of rays diverging in various directions from the source and abruptly bent by refraction or turned by reflection into paths...

A technique used to create an achromatic phase shift based on the principle of geometric phase. The phase shift is experienced by a light beam as a result of a cyclic change in its state of...

The area of optics in which the propagation of light is described by geometrical lines (or rays) governed by Fermat's Principle. Geometrical optics is useful as long as the objects in which the light...

The superposition of satellite or aerial images with a map in order to process and remove distortion. Uses reference points from map to align and apply information.

A crystalline semiconductor material that transmits in the infrared.

Germanium crystal refers to a crystalline form of the element germanium (Ge), which is a metalloid and semiconductor commonly used in various electronic and optical applications. Germanium crystals...

Germicidal ultraviolet (GUV) refers to a specific range of UV radiation that has disinfectant properties capable of killing or inactivating microorganisms, including bacteria, viruses, and fungi. The...

1. A faint second image caused by reflection that is sometimes seen when observing through an optical instrument. 2. With respect to spectroscopy, a false image of a spectral line formed by...

A prefix that is used to represent 109 or 1,000,000,000 in the SI system.

GigE, short for gigabit Ethernet, refers to a standard for high-speed Ethernet communication, capable of transmitting data at rates of up to 1 gigabit per second (Gbps), or 1000 megabits per second...

An optical mounting device that permits adjustment around two perpendicular and intersecting axes of rotation.

A type of birefringent polarizing prism that transmits the extraordinary ray and removes the ordinary ray through total internal reflection. It consists of two calcite prisms with an air gap...

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or phosphoric oxides. Common window or bottle glass is a mixture of soda,...

A furnace, generally electrically heated, with a control system capable of following a cam by which the temperature can be made to go through a definite cycle over a period of days, or even weeks, if...

A capacitor that uses glass as its dielectric material.

An optically pumped solid-state laser in which the active medium is a neodymium ion in a glass rod host. Abbreviated Nd:glass.

Ink used for writing on glass, and also for blackening the edges of lenses to prevent reflection. In the latter case, the refractive index of the ink must closely match that of the glass.

A spectrograph having glass as its refracting component and used in cases where speed and high dispersion are not required. The glass material has a range of about 3700 to 8000 Å.

A type of glass used in telescope mirrors, formed by adding a nucleating agent to standard glass and then heating it until it crystallizes.

A furnace used to heat glass materials. It may be a small laboratory-type furnace for small-scale experiments or large enough to hold gas-fired tanks for the commercial mass production of glass....

A controlled random search process, such as generalized simulated annealing, that has been incorporated into many optical design programs as a way of helping designers find the most suitable lens...

A light source made up of silicon carbide or carborundum. It is resistant to the negative temperature coefficient and mechanical distortion.

Property of a surface which, because of directional reflection, is responsible for the degree to which reflected highlights or the images of objects may be seen as superimposed on the surface.

An electric discharge in a low-pressure gas having a low-current density and a space potential near the cathode that is much higher than the ionization potential of the gas but less than its sparking...

A thermal radiation detector consisting of a small cell with a blackened plastic front face that bulges slightly when heat is received by it. The bulging tilts a small mirror, which, in turn, varies...

A neutral-colored gelatin wedge, cast between glass plates, that is used as an intensity scale in certain types of sensitometers; the greater the thickness of the wedge through which light emitted by...

Temporal jitter at a signal's receiver when amplified noise causes frequency shifts, as with a soliton traveling through an erbium-doped fiber amplifier.

In image processing and machine vision, the rate of change of pixel intensity.

Edge enhancement with a directional characteristic.

In an image, the orientation and magnitude of the rate of change in intensity at any point.

The term gradient-index profile refers to a specific type of refractive index distribution within an optical material. In optics, the refractive index of a material describes how much the speed of...