Laser is a device that emits light (visible light, infrared, UV) through a process of optical amplification based on the stimulated emission of electromagnetic radiation.  The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation”. A laser emits light spatially coherent, allowing a laser to be focused to a tight spot. The laser beam can stay narrow over long distances. This quality of a laser enables its application for lithography and laser cutting.