A laser (acronym for Light Amplification by Stimulated Emission of Radiation)
produces a monochromatic, coherent and collimated bundle of radiation. The exact
wavelength of a laser beam depends on the nature of the used medium and may vary
from X-ray, ultraviolet, visible light, near- and far infrared to microwaves. Ultraviolet
lasers are also known as excimer- or exciplex lasers, referring to the internal process
that takes place in the medium of an ultraviolet laser. In medical science ultraviolet
lasers are commonly used in eye surgery.