LASER

LASER is a  very useful mechanism for emitting electromagnetic radiation,often visible light via the process of stimulated emission.
LASER was invented in 1960 by Charles Hard Townes in an  experiment in the United States Air Force.
LASER actually is an abbreviation for Light Amplification by Stimulated Emission of Radiation. Not many people would think it's an abbreviation but it is.
The emitted light is usually a spatially coherent. Coherent is a property of waves that enables stationary inference. In LASER technology ''coherent light'' denotes a light source that emits light waves of identical frequency,phase and polarization.
LASER light is generally a narrow-wavelength electromagnetic spectrum monochromatic light.