Glossary: U

The wavelength interval of the electromagnetic spectrum that corresponds to ultraviolet light (light that is beyond the visible violet range). UV radiation is often divided into three smaller regions: 320 - 400nm, 280 - 320nm, and 100 - 280nm – defined as UV-A, UV-B, and UV-C, respectively.

Characterization of light that contains random combinations of x and y components of the electric field. Light from sources such as incandescent and fluorescent bulbs, LED spotlights, fiber optic illuminators and sunlight are all examples of unpolarized light.