Definitions: U

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 three-terminal semiconductor having only one PN junction and a stable, open-circuit, negative-resistance property.

A piezoelectric transducer made of a thin strip of piezoelectric material bonded to a strip of metal.

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

Refers to the transistors in which the working current flows through only one type of semiconductor material, either P-type or N-type. In unipolar transistors, the working current consists of either...

A simple electrostatic lens with a focus controlled by a single potential difference.

A unit of measurement in a rangefinder corresponding to 12 s of arc in the apparent field.

A system by which consumer products are assigned a bar code that is read by a scanner at a cash register, enabling computerization of pricing and inventory records.

One of the four functions that allows the computation of a transparent medium's index of refraction, provided the index has been identified for four standard wavelengths.

An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot onboard. UAVs are remotely controlled or autonomously operated, and they can be used for various...

Behaving as though characterized by a series of waves having planes of vibration oriented at all possible azimuths.

A resonator often used for mode control in Fresnel number laser cavities that is highly vulnerable to extremely weak external sources of feedback.

A type of glass contrived by Schott that is highly transparent to ultraviolet radiation.