Fluorescence spectroscopy
From LIMSWiki
Fluorescence spectroscopy aka fluorometry or spectrofluorometry, is a type of electromagnetic spectroscopy which analyzes fluorescence from a sample. It involves using a beam of light (usually ultraviolet light) that excites the electrons in molecules of certain compounds and causes them to emit light (typically but not necessarily visible light) of a lower energy. A complementary technique is absorption spectroscopy.
Devices that measure fluorescence are called fluorometers or fluorimeters.