 Laser light is usually spatially coherent, which means that the light either is emitted in a narrow, low-divergence beam, or can be converted into one with the help of optical components such as lenses.Lasers are used to read compact discs and bar codes, guide missiles, remove ulcers, fabricate steel, precisely measure the distance from Earth to the Moon, record ultradefined images of brain tissue, entertain people in light shows and do thousands of other things.In 1957, American physicist Gordon Gould first theorized the idea and use of laser technology.