Fluorescence, property of emitting visible radiation as the result of absorption of radiation from some other source. The emitted radiation persists only as long as the fluorescent material is subjected to radiation, which may be either electrified particles or waves. The fluorescent radiation generally has a longer wavelength than does the absorbed radiation. If the fluorescent radiation includes waves of the same length as that of the absorbed radiation, it is termed resonance radiation.
See also: Radiation.