acronym stands for Light Amplification by Stimulated Emission of Radiation; this phenomenon is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation; lasers operate in the visible, infrared, or ultraviolet regions of the spectrum and are capable of producing immense heat and power when focused at close range; used in surgical procedures, in diagnosis, and in physiologic studies; lasers used at low power, transmitting light not heat, have been used in wound healing and pain control.