Photonics Dictionary

A dark region created by spherical aberration of an eyepiece's exit pupil. Because of the aberration, an observer's eye must be at different distances from the eyepiece to view different regions of...

An array of spectral lines formed when a beam of electrons, striking a crystalline solid, is scattered. It is used in the analysis of the crystal structure.

In the SI system, prefix meaning one thousand, 103.

A unit of frequency that equals 1000 cps. Abbreviated kHz.

A unit of energy or work that is equal to 1000 (103) joules. Abbreviated kJ.

A mount for an optic element or optics assembly, designed so that all six degrees of freedom are singly constrained. This assures that movement will be prevented, while stress will not be introduced...

That portion of physics concerned with motion in the abstract, such as of points or space figures, and separated from its dynamic properties.

A cathode-ray tube that serves as a picture tube in a television receiver. The signal representing the picture intensity is transmitted to the electron gun grid so that the beam intensity varies with...

An atmospheric nonlinear process unique to CO2 laser wavelengths, whereby CO2 absorbs 10.6-µm radiation and the CO2 molecules in the (100) vibrational state are excited to the (001) level, and...

Lens which, by altering the phase, efficiently images through a holographic process.

A computer-generated kinoform used for data processing because of its use of incoherent light and its wide field of view, which facilitates parallel processing of two-dimensional data.

For any point on a thermal radiator, at thermal equilibrium and for each wavelength, the emissivity in any direction is equal to the absorptance for radiation from the same direction.

A thermionic tube that has a velocity-modulated electron stream and that may be used as a microwave amplifier or oscillator.

An imaging device originally created to image whole mouse brain volumes at microscopic resolution. The main component of the instrument is an automated microtome and microscope capable of producing...

A measurement of the hardness of a material as determined by the penetration depth of a diamond stylus under a specified amount of pressure.

A two-stage illuminating system for a microscope in which the source is imaged in the aperture of the substage condenser by an auxiliary condenser, and the substage condenser in turn forms an image...

A visual, single-unit spectrophotometer with a biprism and a Wollaston prism. The Wollaston prism polarizes coincident images of the two halves of the entrance aperture.

Westinghouse trade name for an alloy of iron, nickel and cobalt, which has the same thermal expansion as glass and therefore is often used for glass-to-metal or ceramic-to-metal seals.

Analysis of the reflection spectrum that allows the determination of the experimental dielectric function.

Astronomical detector consisting of a photocathode isolated from the target by a coin value from which electrons are focused on a nuclear emission, producing tracks on the emission. Track density can...

An arc lamp that has its cavity filled with krypton to produce a light source with unique characteristics.

A two-flux theory in which the radiation is assumed to be composed of two oppositely directed radiation fluxes through a continuous medium. The theory has been widely used to relate the total diffuse...

Pennwalt's trade name for polyvinylidene fluoride, a material used in the jacket of fiber optic cables where low smoke emission is deemed more important than flexibility.

A lab-on-a-chip (LOC) is a miniaturized device that integrates various laboratory functions and capabilities onto a single, compact chip. Also known as microfluidic devices, lab-on-a-chip systems are...

Label-free refers to a technique or method that does not require the use of additional labels, tags, or markers to detect or identify specific components or entities. In various scientific and...

A diagram that shows actual component signals and the basic wiring configuration of a relay logic circuit.

A term applied to an electric charge image in a camera tube that remains for a period of a few frames after its initial formation.

Term for service offered by a vendor who leases a particular wavelength to a customer through DWDM technology. Lambda services are often associated with the leasing of dark fiber.

Transmittance of a solution, or internal transmittance of a transparent solid, is an exponential function of the thickness of the layer.

Flux per unit solid angle leaving a surface in any direction is proportional to the cosine of the angle between that direction and the normal to the surface. A material that obeys Lambert's cosine...

A unit of luminance equal to 1/p candela per square centimeter. (l).

An optical source that has a luminous distribution that is uniform for all directions.

In optics, a plane that emits a flux proportional to the cosine of the angle of the normal; dense opal glass is an example.

A perfectly diffusing surface; the intensity of the light emanating in a given direction from any small surface component is proportional to the cosine of the angle of the normal to the surface. The...

A grating with ridges of rectangular cross section, generally equal in width to the space between. This type of grating may be used as a beam divider.

Composed of layers.

A device designed to concentrate and direct a light source by enclosing the source in it and using a concave reflector to direct the light through its only opening.

In a CD-ROM disc, the reflective area between nonreflective pits representing a binary-language "off'' as opposed to the "on'' signals of the land-to-pit and pit-to-land transitions.

A dark band that may appear in the field of crossed Nicol prisms with a powerful source such as the sun because the light is not strictly parallel and is not extinguished immediately.

A broken circle used as the test object in distinguishing visual acuity. The width of the gap in the circle is equal to the breadth of the black line and one-fifth the circle diameter. Also known as...

A nonluminous area around a negatively charged probe that is inserted into the positive column of an arc or glow discharge.

A method of depositing crystalline films one molecular layer at a time, by dipping the substrate into water containing a polymer that forms a single layer of molecular chains on the surface. This...

A metal tool used to grind lenses with loose abrasive (see diamond cutting tool). The functional surface of the lap is carefully formed to be opposite the curve to be produced on the glass (concave...

An endoscopic surgical instrument that includes a channel for the introduction of supplementary instruments.

1. The process of wearing down the surface of a softer material by rubbing it under pressure against the surface of a harder material that has been formed in the shape opposite to that desired on the...