A laser is an electronic device that emits a light through a process known as optical amplification and is based on stimulating the emission of electromagnetic radiation. Laser is an acronym for the word light amplification by stimulated emission of radiation. Lasers differ from all other light sources as the light they emit is coherent.
Because of this, it is easier to focus a beam of this light on a spot enabling one handle applications like lithography and laser cutting. It is also this coherence that allows the beam to remain narrow over a long distance without distortion or breaking.