The word Laser is an acronym for light amplification by stimulated emission of radiation.A laser is a device that creates and amplifies a narrow, intense beam of coherent light. Atoms emit radiation,we see it every day when the "excited" neon atoms in a neon sign emit light. Normally, they radiate their light in random directions at random times. The result is incoherent light. The trick in generating coherent light of a single or just a few frequencies going in one precise direction is to find the right atoms with the right internal storage mechanisms and create an environment in which they can all cooperate to give up their light at the right time and all in the same direction.