Photonics Dictionary: U

A color space in which equal distances represent equal visually perceived color differences.

In a cathode-ray tube, the region wherein a display on the tube keeps 70 percent or more of its luminance at the center of the viewing area.

Array used in coded-aperture imaging experiments with two-beam CO2 lasers that provide an artifact-free process, faithful reproduction of the true image, and more photon collection than the pinhole...

A form of microfiche that has an information reduction ratio that is greater than 100 to 1.

A dark-field microscope used to view extremely small objects. These objects are suspended in a gas or liquid in an enclosure having a black background. A convergent pencil of bright light enters from...

A highly accurate cathode-ray tube used to display information with the utmost efficient stability and resolution. The information is viewed as a series of points, particularly suited for...

A two- or three-dimensional space grating formed when ultrasonic beams with varied paths of propagation intersect.

The space between diffracting centers of an ultrasonic wave that is forming certain light diffraction spectra.

The formation and display of three-dimensional images by ultrasonic energy. In one technique, the energy pulses from an ultrasonic transducer scan the object through a liquid medium and, receiving...

The optical diffraction spectra formed, or the method that produces them, when a light beam is transmitted through a longitudinal sound field.

The photographic recording that uses ultraviolet radiation to irradiate the microscope sample being examined and to form an image of the object on a photographic medium. The components of the...

Ultraviolet reflectance refers to the ability of a material or surface to reflect UV light. Ultraviolet light is electromagnetic radiation with wavelengths shorter than those of visible light,...

A term describing lenses with both surfaces finished but not yet cut to any form.

In interferometry, the result of superimposing two wavefronts of identical shape, yielding a uniform intensity interference pattern with no bands.