Photonics Dictionary

A plate of electro-optical material that serves to rotate the plane of polarization of a light beam.

That voltage required across a Pockels, Kerr or other electro-optic light modulator to retard one polarization electrical vector by one-half a wavelength relative to the other. It corresponds to a...

A plate containing a uniform pattern of transparent holes in an opaque background, the clear area being nearly equal to the opaque area. Used in the printing process.

The gray-colored tones halfway between shadows and highlights in a reproduced image.

In chemistry, a halide refers to a chemical compound containing one or more halogen atoms bonded to another element. The halogens are a group of elements in the periodic table that includes fluorine...

The development of a transverse electric field in a solid material when it carries an electric current and is placed in a magnetic field that is perpendicular to the current.

1. The faintly hued ring that is seen to surround a light source viewed through fog or light clouds. The size of scattering particles determines the size of the ring. 2. The ring surrounding a...

Any of the five elements astatine, chlorine, fluorine, bromine and iodine, grouped because their chemical properties are similar.

A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a tungsten filament surrounded by a small amount of halogen gas, such as...

The line that divides the two half-images in a coincidence rangefinder. The two halves of the images formed by the two objectives of the instrument must be brought to a point where they coincide...

A device small enough to be held in a hand that uses a magnifying lens and a translucent back to permit the viewing of photographic transparencies.

Usually a dielectric coating on glass or plastic optics; a coating that is comparable in hardness to glass itself.

Text or images printed on paper or another tangible medium, as opposed to those viewed electronically on a cathode-ray-tube screen.

High-modulus elastic fibers that exhibit the following differences from conventional elastic fibers: Increasing temperature decreases recovery force (the fibers are enthalpic vs. conventionally...

The process of sealing laser components by means of frit seals, welding or bonding rather than using epoxy.

A type of x-ray that is capable of deep penetration; its wavelength is about 10-8 cm.

A type of optical fiber in which a silica core is surrounded by a hard polymer or similar material much stronger than the customary cladding material.

In the most general sense, the resistance of a solid surface to damage.

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 instrument designed to calculate the amplitude and phase of the different harmonic elements of a radiation wave utilizing a graph of the wave.

A direct-vision prism made in one piece that can be used only in parallel light.

A test for spherical aberration, coma or astigmatism in which incident rays from a point source are isolated by small holes in a metal disc located close to the lens or mirror under test....

An aggravated form of fog in a polished surface caused by the scattering of light. The defects causing haze are larger than those causing fog, but singly are not large enough to be seen by the...

The ratio between the luminescence of an object and the luminescence of the scattering medium through which it is being viewed.

A filter, used in photography, that absorbs the ultraviolet and extreme blue violet radiation scattered by atmospheric haze.

Designation for the fundamental mode of an optical fiber.

A head-up display (HUD) is a transparent display technology that presents information directly in the field of view of a user, typically without requiring the user to look away from their usual...

The heat-affected zone (HAZ) refers to the portion of a material, typically metal, that experiences changes in its microstructure and mechanical properties due to the heat generated during welding,...

A calorimetric calculation from which the temperature vs. time dependence of any point on a sample can be determined, provided surface and bulk absorption, thermal conductivity and heat transfer...

A type of cooling system in which one fluid is used to carry heat off another without direct contact between the two.

A lamp designed to emit a large amount of infrared radiation; used in applications requiring heat.

A heat sink for a laser is a device designed to absorb and dissipate the excess heat generated by the laser during operation. This is crucial to maintain the laser's performance, prevent overheating,...

The process of subjecting glass to temperature cycling to produce physico-chemical reactions that alter its properties. Similar processes can be accomplished with a laser -- most commonly a CO2,...

In reference to infrared, emissions that are like radio waves but that have a higher frequency.