Narrow beams of intense radiation, produced at a fixed frequency, that depend on the molecules in the cavity of the laser. The word “laser” is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers may function continuously or in a pulsed fashion. The pulsed laser transmits small bursts at a very high energy level; indeed, one of the first uses of the beam was for cutting and welding in heavy industry. It was first introduced sometime between 1957 and 1960 in California.
In medical practice, lasers are now used for cutting tissue; the localized heat that they generate can coagulate blood, arresting bleeding. By passing the laser through fiber optics, the energy can be transmitted to vessels of the heart from some distance away for example, from an incision in the thigh without affecting other surrounding tissues. In ophthalmic surgery, the small diameter of the laser beam allows for the delicate welding of a detached retina back onto its base, thus restoring sight. Birthmarks like the disfiguring port- wine mark can be taken away without the overlying skin been broken or burnt.