Definitions

For each mode in an optical waveguide, the term used to describe the process by which an electromagnetic signal is distorted by virtue of the dependence of the phase and group velocities on...

A photofluorescent compound that, when used with a scintillating substance, absorbs photons and emits related photons having a greater wavelength. In this way a phototube or photocell may employ the...

An optical filter so constructed that the density increases progressively from one end to the other, or angularly around a circular disc.

A photometer that uses a wedge, marked to show its reduction of flux density, to make two light sources equal in intensity for comparison of luminous intensities. This is accomplished by the gradual...

The Weissenberg method, named after the German physicist Karl Weissenberg, is a technique used in x-ray crystallography for obtaining high-quality diffraction patterns from single crystals. This...

A well plate, also known as a microplate or microtiter plate, is a flat plate with multiple small wells or depressions arranged in a grid pattern. Each well serves as a separate container for holding...

A wide-angle lens is a type of camera lens that has a shorter focal length than a standard or normal lens, allowing it to capture a broader field of view. Wide-angle lenses are characterized by their...

After putting a thick photographic emulsion on a front-faced mirror, and exposing the emulsion to monochromatic incident light normal to the face, Wiener discovered, upon developing the emulsion,...

A sealed, hard, magnetic disc drive used for the storage of data in a computer system.

In microscopy, the clear distance between the specimen being viewed and the first optical element of the objective lens.

Term for the brightness of an oscilloscope trace.

The series of processes used to identify and evaluate crystal structure by using crystalline solids to diffract x-rays. In the Laue method, radiation of a wide range of wavelengths is transmitted by...

The collection and detection of x-rays by virtue of their ionizing properties. The ionization may be perceived directly by a gas-filled ionization chamber, photographically, or by correlating...

One of various types of fluorescent screens used to detect x-ray radiation. Photographic film is mildly sensitive to x-rays, but much more sensitive to light. Hence, in photographing x-ray...

An image intensifier that consists of an evacuated tube with a large input phosphor screen at one end. The phosphor screen is in contact with a light-sensitive photocathode that emits electrons....

The method of acquiring characteristic x-ray spectra from microscopic samples by use of the combination of a scanning electron microscope and x-ray spectroscopy.

The arc formed when the rare gas xenon is excited electrically and emits a brilliant white light. Xenon is used to fill electronic and stroboscopic flashlamps, and also large discharge tubes for...

A high-intensity source of incoherent white light in which a capacitor is discharged through a tube of xenon gas; often used as a source of pumping radiation for various optically excited lasers.

Conventional coordinates for optical system analysis, the X-axis being the horizontal, the Y-axis the vertical and the Z-axis the optical axis of the system.

The vertical deflection of an image on a cathode-ray tube screen.

A YAG crystal refers to a solid-state crystal made of yttrium aluminum garnet (YAG), which is a synthetic crystalline material. YAG crystals are known for their exceptional optical properties,...

The method by which Thomas Young in 1802 disproved Newton's corpuscular theory of light by the formation of interference patterns between two beams of light from the same source. This was produced by...

The removal of the zero-order component of the Fourier spectrum distribution of an object with a small, opaque absorber or reflector in the Fourier plane, to produce images that appear bright on a...

A grating that specularly reflects the specified long radiation wavelengths and diffracts the shorter wavelengths off in known directions, eliminating the interference of randomly scattered radiation.

Schott Glass Technologies' trade name for a glass-ceramic material with a very low coefficient of thermal expansion.

A polycrystalline material that transmits in the infrared; it is used as a phosphor in x-ray and television screens.

The sunlight that extends to the earth after scattering from other solar bodies, mostly from meteorite dust of radii equaling 10-3 cm.