The picture screens in television receivers are coated with fluorescent materials known as phosphors that glow when excited by a cathode ray. The interiors of fluorescent lamps have similar coatings, which absorb the invisible but intense ultraviolet components of the primary light source and emit visible light. A special type of fluorescence called stimulated emission occurs in the operation of a laser.
Chemiluminescence is caused by chemical reaction, as when yellow phosphorus oxidizes in air, emitting green luminescence. If the chemical reaction takes place in a living organism, such as the firefly, the process is called bioluminescence. Triboluminescence is luminescence that results from the breaking, scratching, or pulling apart of certain materials. Electro luminescence is luminescence created by a gas in the path of an electrical discharge; examples are lightning and the light of a fluorescent lamp. Photoluminescence is luminescence created when certain materials are irradiated by visible light or ultraviolet light; an example is the phosphorescence of paints. Roentgen luminescence is luminescence produced by X rays bombarding certain materials; an example is X rays on a fluoroscope screen. Son luminescence, observed in some organic liquids, is luminescence produced by ultrahigh-frequency sound waves, or ultrasound.