Fluorescence/Luminescence Spectroscopy

Luminescence is a light emission which represents an excess over the thermal radiation and lasts for a time exceeding the period of electromagnetic oscilation. Luminescent analysis is performed using the intrinsic Luminescence of materials under observation, or special markers (luminophors) are added when the material itself does not demonstrate luminescent properties.
Fluorescence is a "fast" Photoluminescence. The effect is widely used in such everyday practical applications as industrial and residential lightning as an analytical technique in science and as a quality and process control method in industry.