A laser, an acronym lor light amplification by stimulated emission of radiation, is a device for generating a high-intensity, ostensibly parallel beam of monochromatic (single wavelength) electromagnetic radiation. The possibility of stimulated emission was predicted by Einstein in I9I7; based on the work of Gordon in 1955 and Schawlow and Townes in 1958, Maiman created the first operational laser in 1960, a ruby laser emitting a brilliant red beam of light. This was followed within 3 years by the development of the argon, carbon dioxide (C02 ) , and neodymium:yttrium-aluminum- garnet (Nd:YAG) lasers, which remain the most widely used lasers in medicine
